Issue #3251293: pattern_wrapper_entity_reference_formatter not working drupal commerce

src/Plugin/Field/FieldFormatter/PatternWrapperEntityReferenceFormatter.php

@@ -240,7 +240,7 @@ class PatternWrapperEntityReferenceFormatter extends EntityReferenceEntityFormat
       'type' => 'field_formatter',
       'entity' => $entity,
     ];
-    return $build;
+    return [0 => $build];
   }
 
   /**