diff -u b/src/Plugin/DisplayBuilder/StandardDisplayBuilder.php b/src/Plugin/DisplayBuilder/StandardDisplayBuilder.php
--- b/src/Plugin/DisplayBuilder/StandardDisplayBuilder.php
+++ b/src/Plugin/DisplayBuilder/StandardDisplayBuilder.php
@@ -120,17 +120,26 @@
 
           $content = $block->build();
           if (!is_array($content)) {
-            throw new \LogicException(new FormattableMarkup('Block %block build method has to return an array.', ['%block' => $block_id]));
+            $class = get_class($block);
+            throw new \LogicException(sprintf('BlockPluginInterface::build method has to return an array. Class returning non-array value is: %s', $class));
           }
 
-          // If the block is not empty, build the block and bubble its
-          // attributes up if possible. This allows modules like Quickedit to
-          // function.
           // If the block is empty, instead of trying to render the block
           // correctly return just #cache, so that the render system knows the
           // reasons (cache contexts & tags) why this block is empty.
           // @see \Drupal\block\BlockViewBuilder::preRender()
-          if (!Element::isEmpty($content)) {
+          if (Element::isEmpty($content)) {
+            $block_render_array = [];
+            $cacheable_metadata = CacheableMetadata::createFromObject($block_render_array);
+            $cacheable_metadata->applyTo($block_render_array);
+            if (isset($content['#cache'])) {
+              $block_render_array['#cache'] = $content['#cache'];
+            }
+          }
+          else {
+            // If the block is not empty, build the block and bubble its
+            // attributes up if possible. This allows modules like Quickedit to
+            // function.
             foreach (['#attributes', '#contextual_links'] as $property) {
               if (isset($content[$property])) {
                 $block_render_array[$property] += $content[$property];
@@ -139,14 +148,6 @@
             }
             $block_render_array['content'] = $content;
           }
-          else {
-            $block_render_array = [];
-            $cacheable_metadata = CacheableMetadata::createFromObject($block_render_array);
-            $cacheable_metadata->applyTo($block_render_array);
-            if (isset($content['#cache'])) {
-              $block_render_array['#cache'] = $content['#cache'];
-            }
-          }
 
           $build[$region][$block_id] = $block_render_array;
         }