diff --git a/app/activitypub/routes.py b/app/activitypub/routes.py
index 7508985c..498fdb92 100644
--- a/app/activitypub/routes.py
+++ b/app/activitypub/routes.py
@@ -1339,7 +1339,7 @@ def user_inbox(actor):
                                     activity_log.result = 'success'
                                     db.session.commit()
                                     if post_being_replied_to.author.is_local():
-                                        inform_followers_of_post_update(post_being_replied_to, user.instance_id)
+                                        inform_followers_of_post_update(post_being_replied_to.id, user.instance_id)
 
         except VerificationError:
             activity_log.result = 'failure'
diff --git a/app/activitypub/util.py b/app/activitypub/util.py
index e6091e2e..4a23dd92 100644
--- a/app/activitypub/util.py
+++ b/app/activitypub/util.py
@@ -2557,15 +2557,16 @@ def resolve_remote_post_from_search(uri: str) -> Union[Post, None]:
 # This would need for posts to have things like a 'Replies' collection and a 'Likes' collection, so these can be downloaded when the post updates
 # Using collecions like this (as PeerTube does) circumvents the problem of not having a remote user's private key.
 # The problem of what to do for remote user's activity on a remote user's post in a local community still exists (can't Announce it, can't inform of post update)
-def inform_followers_of_post_update(post: Post, sending_instance_id: int):
+def inform_followers_of_post_update(post_id: int, sending_instance_id: int):
     if current_app.debug:
-        inform_followers_of_post_update_task(post, sending_instance_id)
+        inform_followers_of_post_update_task(post_id, sending_instance_id)
     else:
-        inform_followers_of_post_update_task.delay(post, sending_instance_id)
+        inform_followers_of_post_update_task.delay(post_id, sending_instance_id)
 
 
 @celery.task
-def inform_followers_of_post_update_task(post: Post, sending_instance_id: int):
+def inform_followers_of_post_update_task(post_id: int, sending_instance_id: int):
+    post = Post.query.get(post_id)
     page_json = post_to_page(post)
     page_json['updated'] = ap_datetime(utcnow())
     update_json = {
diff --git a/app/post/routes.py b/app/post/routes.py
index 2c4b7952..d14af0ea 100644
--- a/app/post/routes.py
+++ b/app/post/routes.py
@@ -582,7 +582,7 @@ def poll_vote(post_id):
         poll_votes = PollChoice.query.join(PollChoiceVote, PollChoiceVote.choice_id == PollChoice.id).filter(PollChoiceVote.post_id == post.id, PollChoiceVote.user_id == current_user.id).all()
         for pv in poll_votes:
             if post.author.is_local():
-                inform_followers_of_post_update(post, 1)
+                inform_followers_of_post_update(post.id, 1)
             else:
                 pollvote_json = {
                   '@context': default_context(),