diff --git a/boards/models/post/__init__.py b/boards/models/post/__init__.py
--- a/boards/models/post/__init__.py
+++ b/boards/models/post/__init__.py
@@ -152,13 +152,6 @@ class Post(models.Model, Viewable):
     def get_thread_id(self):
         return self.thread_id
 
-    def get_threads(self) -> QuerySet:
-        """
-        Gets post's thread.
-        """
-
-        return self.threads
-
     def _get_cache_key(self):
         return [datetime_to_epoch(self.last_edit_time)]
 
diff --git a/boards/models/thread.py b/boards/models/thread.py
--- a/boards/models/thread.py
+++ b/boards/models/thread.py
@@ -238,14 +238,12 @@ class Thread(models.Model):
     def update_posts_time(self, exclude_posts=None):
         last_edit_time = self.last_edit_time
 
-        for post in self.multi_replies.all():
+        for post in self.replies.all():
             if exclude_posts is None or post not in exclude_posts:
                 # Manual update is required because uids are generated on save
                 post.last_edit_time = last_edit_time
                 post.save(update_fields=['last_edit_time'])
 
-                post.get_threads().update(last_edit_time=last_edit_time)
-
     def notify_clients(self):
         if not settings.get_bool('External', 'WebsocketsEnabled'):
             return