 core/modules/big_pipe/src/Render/BigPipe.php       |  4 ++--
 .../big_pipe/src/Render/BigPipeInterface.php       | 10 ++++-----
 .../src/Render/Placeholder/BigPipeStrategy.php     |  4 ++--
 .../src/Tests/BigPipePlaceholderTestCases.php      | 24 ++++++++++----------
 core/modules/big_pipe/src/Tests/BigPipeTest.php    |  2 +-
 .../big_pipe_regression_test.routing.yml           |  7 ++++++
 .../src/BigPipeRegressionTestController.php        | 26 ++++++++++++++++++++++
 .../FunctionalJavascript/BigPipeRegressionTest.php | 12 ++++++++++
 8 files changed, 67 insertions(+), 22 deletions(-)

diff --git a/core/modules/big_pipe/src/Render/BigPipe.php b/core/modules/big_pipe/src/Render/BigPipe.php
index 1894aa9..c299157 100644
--- a/core/modules/big_pipe/src/Render/BigPipe.php
+++ b/core/modules/big_pipe/src/Render/BigPipe.php
@@ -545,12 +545,12 @@ protected function renderPlaceholder($placeholder, array $placeholder_render_arr
    *   only keep the first occurrence.
    */
   protected function getPlaceholderOrder($html, $placeholders) {
-    $fragments = explode('<div data-big-pipe-placeholder-id="', $html);
+    $fragments = explode('<span data-big-pipe-placeholder-id="', $html);
     array_shift($fragments);
     $placeholder_ids = [];
 
     foreach ($fragments as $fragment) {
-      $t = explode('"></div>', $fragment, 2);
+      $t = explode('"></span>', $fragment, 2);
       $placeholder_id = $t[0];
       $placeholder_ids[] = $placeholder_id;
     }
diff --git a/core/modules/big_pipe/src/Render/BigPipeInterface.php b/core/modules/big_pipe/src/Render/BigPipeInterface.php
index 6d0e5a7..b16e50c 100644
--- a/core/modules/big_pipe/src/Render/BigPipeInterface.php
+++ b/core/modules/big_pipe/src/Render/BigPipeInterface.php
@@ -52,7 +52,7 @@
  * 1. BigPipe placeholders: 1 HtmlResponse + N embedded AjaxResponses.
  *   - Before a BigPipe response is sent, it is just a HTML response that
  *     contains BigPipe placeholders. Those placeholders look like
- *     <div data-big-pipe-placeholder-id="…"></div>. JavaScript is used to
+ *     <span data-big-pipe-placeholder-id="…"span>. JavaScript is used to
  *     replace those placeholders.
  *     Therefore these placeholders are actually sent to the client.
  *   - The Skeleton of course has attachments, including most notably asset
@@ -79,7 +79,7 @@
  *   - Before a BigPipe response is sent, it is just a HTML response that
  *     contains no-JS BigPipe placeholders. Those placeholders can take two
  *     different forms:
- *     1. <div data-big-pipe-nojs-placeholder-id="…"></div> if it's a
+ *     1. <span data-big-pipe-nojs-placeholder-id="…"></span> if it's a
  *        placeholder that will be replaced by HTML
  *     2. big_pipe_nojs_placeholder_attribute_safe:… if it's a placeholder
  *        inside a HTML attribute, in which 1. would be invalid (angle brackets
@@ -112,11 +112,11 @@
  * Combining all of the above, when using both BigPipe placeholders and no-JS
  * BigPipe placeholders, we therefore send: 1 HtmlResponse + M Embedded HTML
  * Responses + N Embedded AJAX Responses. Schematically, we send these chunks:
- *  1. Byte zero until 1st no-JS placeholder: headers + <html><head /><div>…</div>
+ *  1. Byte zero until 1st no-JS placeholder: headers + <html><head /><span>…</span>
  *  2. 1st no-JS placeholder replacement: <link rel="stylesheet" …><script …><content>
- *  3. Content until 2nd no-JS placeholder: <div>…</div>
+ *  3. Content until 2nd no-JS placeholder: <span>…</span>
  *  4. 2nd no-JS placeholder replacement: <link rel="stylesheet" …><script …><content>
- *  5. Content until 3rd no-JS placeholder: <div>…</div>
+ *  5. Content until 3rd no-JS placeholder: <span>…</span>
  *  6. [… repeat until all no-JS placeholder replacements are sent …]
  *  7. Send content after last no-JS placeholder.
  *  8. Send script_bottom (markup to load bottom i.e. non-critical JS).
diff --git a/core/modules/big_pipe/src/Render/Placeholder/BigPipeStrategy.php b/core/modules/big_pipe/src/Render/Placeholder/BigPipeStrategy.php
index 91ad604..c61c25c 100644
--- a/core/modules/big_pipe/src/Render/Placeholder/BigPipeStrategy.php
+++ b/core/modules/big_pipe/src/Render/Placeholder/BigPipeStrategy.php
@@ -183,7 +183,7 @@ protected static function createBigPipeJsPlaceholder($original_placeholder, arra
     $big_pipe_placeholder_id = static::generateBigPipePlaceholderId($original_placeholder, $placeholder_render_array);
 
     return [
-      '#markup' => '<div data-big-pipe-placeholder-id="' . Html::escape($big_pipe_placeholder_id) . '"></div>',
+      '#markup' => '<span data-big-pipe-placeholder-id="' . Html::escape($big_pipe_placeholder_id) . '"></span>',
       '#cache' => [
         'max-age' => 0,
         'contexts' => [
@@ -221,7 +221,7 @@ protected static function createBigPipeJsPlaceholder($original_placeholder, arra
    */
   protected static function createBigPipeNoJsPlaceholder($original_placeholder, array $placeholder_render_array, $placeholder_must_be_attribute_safe = FALSE) {
     if (!$placeholder_must_be_attribute_safe) {
-      $big_pipe_placeholder = '<div data-big-pipe-nojs-placeholder-id="' . Html::escape(static::generateBigPipePlaceholderId($original_placeholder, $placeholder_render_array)) . '"></div>';
+      $big_pipe_placeholder = '<span data-big-pipe-nojs-placeholder-id="' . Html::escape(static::generateBigPipePlaceholderId($original_placeholder, $placeholder_render_array)) . '"></span>';
     }
     else {
       $big_pipe_placeholder = 'big_pipe_nojs_placeholder_attribute_safe:' . Html::escape($original_placeholder);
diff --git a/core/modules/big_pipe/src/Tests/BigPipePlaceholderTestCases.php b/core/modules/big_pipe/src/Tests/BigPipePlaceholderTestCases.php
index d2db3cb..1467ad3 100644
--- a/core/modules/big_pipe/src/Tests/BigPipePlaceholderTestCases.php
+++ b/core/modules/big_pipe/src/Tests/BigPipePlaceholderTestCases.php
@@ -61,7 +61,7 @@ public static function cases(ContainerInterface $container = NULL, AccountInterf
     );
     $status_messages->bigPipePlaceholderId = 'callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e';
     $status_messages->bigPipePlaceholderRenderArray = [
-      '#markup' => '<div data-big-pipe-placeholder-id="callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e"></div>',
+      '#markup' => '<span data-big-pipe-placeholder-id="callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e"></span>',
       '#cache' => $cacheability_depends_on_session_and_nojs_cookie,
       '#attached' => [
         'library' => ['big_pipe/big_pipe'],
@@ -75,13 +75,13 @@ public static function cases(ContainerInterface $container = NULL, AccountInterf
         ],
       ],
     ];
-    $status_messages->bigPipeNoJsPlaceholder = '<div data-big-pipe-nojs-placeholder-id="callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e"></div>';
+    $status_messages->bigPipeNoJsPlaceholder = '<span data-big-pipe-nojs-placeholder-id="callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e"></span>';
     $status_messages->bigPipeNoJsPlaceholderRenderArray = [
-      '#markup' => '<div data-big-pipe-nojs-placeholder-id="callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e"></div>',
+      '#markup' => '<span data-big-pipe-nojs-placeholder-id="callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e"></span>',
       '#cache' => $cacheability_depends_on_session_and_nojs_cookie,
       '#attached' => [
         'big_pipe_nojs_placeholders' => [
-          '<div data-big-pipe-nojs-placeholder-id="callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e"></div>' => $status_messages->placeholderRenderArray,
+          '<span data-big-pipe-nojs-placeholder-id="callback=Drupal%5CCore%5CRender%5CElement%5CStatusMessages%3A%3ArenderMessages&amp;args[0]&amp;token=a8c34b5e"></span>' => $status_messages->placeholderRenderArray,
         ],
       ],
     ];
@@ -225,7 +225,7 @@ public static function cases(ContainerInterface $container = NULL, AccountInterf
     );
     $current_time->bigPipePlaceholderId = 'timecurrent-timetime';
     $current_time->bigPipePlaceholderRenderArray = [
-      '#markup' => '<div data-big-pipe-placeholder-id="timecurrent-timetime"></div>',
+      '#markup' => '<span data-big-pipe-placeholder-id="timecurrent-timetime"></span>',
       '#cache' => $cacheability_depends_on_session_and_nojs_cookie,
       '#attached' => [
         'library' => ['big_pipe/big_pipe'],
@@ -248,13 +248,13 @@ public static function cases(ContainerInterface $container = NULL, AccountInterf
         'settings' => NULL,
       ],
     ];
-    $current_time->bigPipeNoJsPlaceholder = '<div data-big-pipe-nojs-placeholder-id="timecurrent-timetime"></div>';
+    $current_time->bigPipeNoJsPlaceholder = '<span data-big-pipe-nojs-placeholder-id="timecurrent-timetime"></span>';
     $current_time->bigPipeNoJsPlaceholderRenderArray = [
-      '#markup' => '<div data-big-pipe-nojs-placeholder-id="timecurrent-timetime"></div>',
+      '#markup' => '<span data-big-pipe-nojs-placeholder-id="timecurrent-timetime"></span>',
       '#cache' => $cacheability_depends_on_session_and_nojs_cookie,
       '#attached' => [
         'big_pipe_nojs_placeholders' => [
-          '<div data-big-pipe-nojs-placeholder-id="timecurrent-timetime"></div>' => $current_time->placeholderRenderArray,
+          '<span data-big-pipe-nojs-placeholder-id="timecurrent-timetime"></span>' => $current_time->placeholderRenderArray,
         ],
       ],
     ];
@@ -274,7 +274,7 @@ public static function cases(ContainerInterface $container = NULL, AccountInterf
     );
     $exception->bigPipePlaceholderId = 'callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3Aexception&amp;args[0]=llamas&amp;args[1]=suck&amp;token=68a75f1a';
     $exception->bigPipePlaceholderRenderArray = [
-      '#markup' => '<div data-big-pipe-placeholder-id="callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3Aexception&amp;args[0]=llamas&amp;args[1]=suck&amp;token=68a75f1a"></div>',
+      '#markup' => '<span data-big-pipe-placeholder-id="callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3Aexception&amp;args[0]=llamas&amp;args[1]=suck&amp;token=68a75f1a"></span>',
       '#cache' => $cacheability_depends_on_session_and_nojs_cookie,
       '#attached' => [
         'library' => ['big_pipe/big_pipe'],
@@ -289,7 +289,7 @@ public static function cases(ContainerInterface $container = NULL, AccountInterf
       ],
     ];
     $exception->embeddedAjaxResponseCommands = NULL;
-    $exception->bigPipeNoJsPlaceholder = '<div data-big-pipe-nojs-placeholder-id="callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3Aexception&amp;args[0]=llamas&amp;args[1]=suck&amp;token=68a75f1a"></div>';
+    $exception->bigPipeNoJsPlaceholder = '<span data-big-pipe-nojs-placeholder-id="callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3Aexception&amp;args[0]=llamas&amp;args[1]=suck&amp;token=68a75f1a"></span>';
     $exception->bigPipeNoJsPlaceholderRenderArray = [
       '#markup' => $exception->bigPipeNoJsPlaceholder,
       '#cache' => $cacheability_depends_on_session_and_nojs_cookie,
@@ -314,7 +314,7 @@ public static function cases(ContainerInterface $container = NULL, AccountInterf
     );
     $embedded_response_exception->bigPipePlaceholderId = 'callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3AresponseException&amp;&amp;token=2a9bd022';
     $embedded_response_exception->bigPipePlaceholderRenderArray = [
-      '#markup' => '<div data-big-pipe-placeholder-id="callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3AresponseException&amp;&amp;token=2a9bd022"></div>',
+      '#markup' => '<span data-big-pipe-placeholder-id="callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3AresponseException&amp;&amp;token=2a9bd022"></span>',
       '#cache' => $cacheability_depends_on_session_and_nojs_cookie,
       '#attached' => [
         'library' => ['big_pipe/big_pipe'],
@@ -329,7 +329,7 @@ public static function cases(ContainerInterface $container = NULL, AccountInterf
       ],
     ];
     $embedded_response_exception->embeddedAjaxResponseCommands = NULL;
-    $embedded_response_exception->bigPipeNoJsPlaceholder = '<div data-big-pipe-nojs-placeholder-id="callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3AresponseException&amp;&amp;token=2a9bd022"></div>';
+    $embedded_response_exception->bigPipeNoJsPlaceholder = '<span data-big-pipe-nojs-placeholder-id="callback=%5CDrupal%5Cbig_pipe_test%5CBigPipeTestController%3A%3AresponseException&amp;&amp;token=2a9bd022"></span>';
     $embedded_response_exception->bigPipeNoJsPlaceholderRenderArray = [
       '#markup' => $embedded_response_exception->bigPipeNoJsPlaceholder,
       '#cache' => $cacheability_depends_on_session_and_nojs_cookie,
diff --git a/core/modules/big_pipe/src/Tests/BigPipeTest.php b/core/modules/big_pipe/src/Tests/BigPipeTest.php
index a3f773e..59fad2d 100644
--- a/core/modules/big_pipe/src/Tests/BigPipeTest.php
+++ b/core/modules/big_pipe/src/Tests/BigPipeTest.php
@@ -353,7 +353,7 @@ protected function assertBigPipePlaceholders(array $expected_big_pipe_placeholde
     foreach ($expected_big_pipe_placeholders as $big_pipe_placeholder_id => $expected_ajax_response) {
       $this->pass('BigPipe placeholder: ' . $big_pipe_placeholder_id, 'Debug');
       // Verify expected placeholder.
-      $expected_placeholder_html = '<div data-big-pipe-placeholder-id="' . $big_pipe_placeholder_id . '"></div>';
+      $expected_placeholder_html = '<span data-big-pipe-placeholder-id="' . $big_pipe_placeholder_id . '"></span>';
       $this->assertRaw($expected_placeholder_html, 'BigPipe placeholder for placeholder ID "' . $big_pipe_placeholder_id . '" found.');
       $pos = strpos($this->getRawContent(), $expected_placeholder_html);
       $placeholder_positions[$pos] = $big_pipe_placeholder_id;
diff --git a/core/modules/big_pipe/tests/modules/big_pipe_regression_test/big_pipe_regression_test.routing.yml b/core/modules/big_pipe/tests/modules/big_pipe_regression_test/big_pipe_regression_test.routing.yml
index a2fc417..bd0543b 100644
--- a/core/modules/big_pipe/tests/modules/big_pipe_regression_test/big_pipe_regression_test.routing.yml
+++ b/core/modules/big_pipe/tests/modules/big_pipe_regression_test/big_pipe_regression_test.routing.yml
@@ -4,3 +4,10 @@ big_pipe_regression_test.2678662:
     _controller: '\Drupal\big_pipe_regression_test\BigPipeRegressionTestController::regression2678662'
   requirements:
     _access: 'TRUE'
+
+big_pipe_regression_test.2802923:
+  path: '/big_pipe_regression_test/2802923'
+  defaults:
+    _controller: '\Drupal\big_pipe_regression_test\BigPipeRegressionTestController::regression2802923'
+  requirements:
+    _access: 'TRUE'
diff --git a/core/modules/big_pipe/tests/modules/big_pipe_regression_test/src/BigPipeRegressionTestController.php b/core/modules/big_pipe/tests/modules/big_pipe_regression_test/src/BigPipeRegressionTestController.php
index f42c89c..50e618b 100644
--- a/core/modules/big_pipe/tests/modules/big_pipe_regression_test/src/BigPipeRegressionTestController.php
+++ b/core/modules/big_pipe/tests/modules/big_pipe_regression_test/src/BigPipeRegressionTestController.php
@@ -17,4 +17,30 @@ public function regression2678662() {
     ];
   }
 
+  /**
+   * @see \Drupal\Tests\big_pipe\FunctionalJavascript\BigPipeRegressionTest::testMultipleBodies_2678662()
+   */
+  public function regression2802923() {
+    return [
+      '#prefix' => BigPipeMarkup::create('<p>Hi, my train will arrive at '),
+      'time' => [
+        '#lazy_builder' => [static::class . '::currentTime', []],
+        '#create_placeholder' => TRUE,
+      ],
+      '#suffix' => BigPipeMarkup::create(' — will I still be able to catch the connection to the center?</p>'),
+    ];
+  }
+
+  /**
+   * #lazy_builder callback; builds <time> markup with current time.
+   *
+   * @return array
+   */
+  public static function currentTime() {
+    return [
+      '#markup' => '<time datetime="' . date('Y-m-d', time()) . '"></time>',
+      '#cache' => ['max-age' => 0]
+    ];
+  }
+
 }
diff --git a/core/modules/big_pipe/tests/src/FunctionalJavascript/BigPipeRegressionTest.php b/core/modules/big_pipe/tests/src/FunctionalJavascript/BigPipeRegressionTest.php
index a99d5fc..b4da7b0 100644
--- a/core/modules/big_pipe/tests/src/FunctionalJavascript/BigPipeRegressionTest.php
+++ b/core/modules/big_pipe/tests/src/FunctionalJavascript/BigPipeRegressionTest.php
@@ -184,4 +184,16 @@ public function testMessages_2712935() {
     }
   }
 
+  /**
+   * Ensure default BigPipe placeholder HTML cannot split paragraphs.
+   *
+   * @see https://www.drupal.org/node/2802923
+   */
+  public function testPlaceholderInParagraph_2802923() {
+    $this->drupalLogin($this->drupalCreateUser());
+    $this->drupalGet(Url::fromRoute('big_pipe_regression_test.2802923'));
+
+    $this->assertJsCondition('document.querySelectorAll(\'p\').length === 1');
+  }
+
 }
