diff --git a/src/Entity/Digest.php b/src/Entity/Digest.php
index 084b9c7..2bd0da3 100644
--- a/src/Entity/Digest.php
+++ b/src/Entity/Digest.php
@@ -91,13 +91,6 @@ class Digest extends ConfigEntityBase implements DigestInterface {
    */
   protected $send_at;
 
-  /**
-   * A loaded CronExpression instance of the 'send_at' value.
-   *
-   * @var \Cron\CronExpression
-   */
-  private $send_at_instance;
-
   /**
    * The ID block used to create the body of this digest.
    *
@@ -105,13 +98,6 @@ class Digest extends ConfigEntityBase implements DigestInterface {
    */
   protected $display_block;
 
-  /**
-   * The loaded instance of the display block for this digest.
-   *
-   * @var \Drupal\Core\Block\BlockPluginInterface
-   */
-  private $display_block_instance;
-
   /**
    * The block plugin manager.
    *
@@ -188,12 +174,12 @@ class Digest extends ConfigEntityBase implements DigestInterface {
    */
   public function getSendAt() {
 
-    // Load the CronExpression if it has not already been loaded.
-    if (!isset($this->send_at_instance)) {
-      $this->send_at_instance = new CronExpression($this->send_at);
+    try {
+      return new CronExpression($this->send_at);
+    }
+    catch (\Throwable $exception) {
+      return NULL;
     }
-
-    return $this->send_at_instance;
 
   }
 
@@ -210,7 +196,6 @@ class Digest extends ConfigEntityBase implements DigestInterface {
     }
 
     $this->send_at = $setTo->getExpression();
-    $this->send_at_instance = $setTo;
 
     return $this;
 
@@ -220,15 +205,7 @@ class Digest extends ConfigEntityBase implements DigestInterface {
    * {@inheritDoc}
    */
   public function getDisplayBlock() {
-
-    // Load the block if it has not already been loaded.
-    if (!isset($this->display_block_instance)) {
-      $this->display_block_instance =
-        $this->blockManager->createInstance($this->display_block);
-    }
-
-    return $this->display_block_instance;
-
+    return $this->blockManager->createInstance($this->display_block);
   }
 
   /**
@@ -242,7 +219,6 @@ class Digest extends ConfigEntityBase implements DigestInterface {
 
     // Update the block ID and instance.
     $this->display_block = $setTo;
-    $this->display_block_instance = $this->blockManager->createInstance($setTo);
 
     return $this;
 
diff --git a/src/Entity/DigestInterface.php b/src/Entity/DigestInterface.php
index 9912483..9bf74f5 100644
--- a/src/Entity/DigestInterface.php
+++ b/src/Entity/DigestInterface.php
@@ -68,8 +68,9 @@ interface DigestInterface extends ConfigEntityInterface {
   /**
    * Returns the current value of 'send_at' as a CronExpression.
    *
-   * @return \Cron\CronExpression
+   * @return \Cron\CronExpression|null
    *   The CronExpression representation of 'send_at'.
+   *   Returns NULL if no send at value is invalid or was not set.
    */
   public function getSendAt();
 
@@ -92,6 +93,8 @@ interface DigestInterface extends ConfigEntityInterface {
    *
    * @return \Drupal\Core\Block\BlockPluginInterface
    *   The block plugin for this digest.
+   *   If the value for the display block ID is invalid the 'broken' block will
+   *   be returned.
    */
   public function getDisplayBlock();
 
diff --git a/tests/src/Kernel/Entity/DigestTest.php b/tests/src/Kernel/Entity/DigestTest.php
index 7052091..a1269b3 100644
--- a/tests/src/Kernel/Entity/DigestTest.php
+++ b/tests/src/Kernel/Entity/DigestTest.php
@@ -114,30 +114,43 @@ class DigestTest extends EntityKernelTestBase {
   public function testSendAt() {
 
     $valid_cron = '* * * * *';
-    $invalid_cron = 'I am not cron';
+
+    // Getting the send at before it has been set should return null.
+    $this->assertNull($this->digest->getSendAt());
+
+    // An invalid cron value should also return NULL.
+    $this->digest->set('send_at', 'Not cron');
+    $this->assertNull($this->digest->getSendAt());
 
     // Should successfully set and retrieve a cron expression.
     $this->digest->setSendAt($valid_cron);
     $expression = $this->digest->getSendAt()->getExpression();
     $this->assertEqual($valid_cron, $expression);
 
-    // An exception should be thrown for invalid cron strings.
-    $this->expectException(\InvalidArgumentException::class);
-    $this->digest->setSendAt($invalid_cron);
+    try {
 
-    // The value of send at should not have changed.
-    $expression = $this->digest->getSendAt()->getExpression();
-    $this->assertEqual($valid_cron, $expression);
+      // An exception should be thrown for invalid cron strings.
+      $this->digest->setSendAt('I am not cron');
+      $this->fail('No exception thrown for invalid cron expression.');
 
-    // Reset the digest.
-    $this->digest = $this->digestStorage->create([
-      'id' => 'my_digest',
-    ]);
-    $this->digest->save();
+    }
+    catch (\InvalidArgumentException $exception) {
+
+      // The value of send at should not have changed.
+      $expression = $this->digest->getSendAt()->getExpression();
+      $this->assertEqual($valid_cron, $expression);
+
+    }
+
+    // The correct expression should be returned after updating the value
+    // through generic entity methods.
+    $valid_cron = '0 0 * * 5';
+    $this->digest->set('send_at', $valid_cron);
+    $expression = $this->digest->getSendAt();
+    $this->assertEqual($valid_cron, $expression);
 
     // The same results should occur if a CronExpression object is passed in.
     $cron_expression = new CronExpression($valid_cron);
-
     $this->digest->setSendAt($cron_expression);
     $expression = $this->digest->getSendAt();
     $this->assertEqual($cron_expression, $expression);
@@ -154,15 +167,30 @@ class DigestTest extends EntityKernelTestBase {
 
     $valid_block = 'page_title_block';
 
+    // Should successfully set and retrieve the display block.
     $this->digest->setDisplayBlock($valid_block);
     $block = $this->digest->getDisplayBlock();
     $this->assertEqual($valid_block, $block->getPluginId());
 
-    // An exception should be thrown for invalid IDs.
-    $this->expectException(PluginException::class);
-    $this->digest->setDisplayBlock('Not a block');
+    try {
+
+      // An exception should be thrown for invalid IDs.
+      $this->digest->setDisplayBlock('Not a block');
+      $this->fail('No exception thrown for invalid block ID.');
+
+    }
+    catch (PluginException $exception) {
+
+      // The value of send at should not have changed.
+      $block = $this->digest->getDisplayBlock();
+      $this->assertEqual($valid_block, $block->getPluginId());
+
+    }
 
-    // The value of send at should not have changed.
+    // The correct block should be returned after updating the value through
+    // generic entity methods.
+    $valid_block = 'user_login_block';
+    $this->digest->set('display_block', $valid_block);
     $block = $this->digest->getDisplayBlock();
     $this->assertEqual($valid_block, $block->getPluginId());