diff --git a/v4/Models/Post.php b/v4/Models/Post.php
index 5b58d01252..e89e57f853 100644
--- a/v4/Models/Post.php
+++ b/v4/Models/Post.php
@@ -220,6 +220,9 @@ public function getRules()
                     ]
                 )
             ],
+            'post_content.*.form_id'                   => [
+                'same:form_id'
+            ],
             'locale',
             'post_date'
         ];