diff --git a/app/serializers/basic_post_serializer.rb b/app/serializers/basic_post_serializer.rb
index 9d57a1c6f1c..32c14b5c72d 100644
--- a/app/serializers/basic_post_serializer.rb
+++ b/app/serializers/basic_post_serializer.rb
@@ -10,6 +10,8 @@ class BasicPostSerializer < ApplicationSerializer
              :cooked,
              :cooked_hidden
 
+  attr_accessor :topic_view
+
   def name
     object.user && object.user.name
   end
@@ -41,20 +43,27 @@ class BasicPostSerializer < ApplicationSerializer
       cooked = object.filter_quotes(@parent_post)
 
       if scope&.user
-        group = Group
-          .joins('JOIN group_users ON groups.id = group_users.group_id')
-          .find_by(
-            id: object.custom_fields['requested_group_id'].to_i,
-            group_users: { user_id: scope.user.id, owner: true }
-          )
 
-        if group
-          cooked << <<~EOF
-            <hr />
-            <a href="#{Discourse.base_uri}/g/#{group.name}/requests">
-              #{I18n.t('groups.request_membership_pm.handle')}
-            </a>
-          EOF
+        # PERF: this should not run on every post, only specific ones
+        # also, why is this in basic post serializer?
+        requested_group_id = post_custom_fields['requested_group_id'].to_i
+
+        if requested_group_id > 0
+          group = Group
+            .joins('JOIN group_users ON groups.id = group_users.group_id')
+            .find_by(
+              id: object.custom_fields['requested_group_id'].to_i,
+              group_users: { user_id: scope.user.id, owner: true }
+            )
+
+          if group
+            cooked << <<~EOF
+              <hr />
+              <a href="#{Discourse.base_uri}/g/#{group.name}/requests">
+                #{I18n.t('groups.request_membership_pm.handle')}
+              </a>
+            EOF
+          end
         end
       end
 
@@ -66,4 +75,12 @@ class BasicPostSerializer < ApplicationSerializer
     SiteSetting.enable_names?
   end
 
+  def post_custom_fields
+    @post_custom_fields ||= if @topic_view
+      (@topic_view.post_custom_fields || {})[object.id] || {}
+    else
+      object.custom_fields
+    end
+  end
+
 end
diff --git a/app/serializers/post_serializer.rb b/app/serializers/post_serializer.rb
index 2221359aafd..7ab24caacc5 100644
--- a/app/serializers/post_serializer.rb
+++ b/app/serializers/post_serializer.rb
@@ -4,7 +4,6 @@ class PostSerializer < BasicPostSerializer
 
   # To pass in additional information we might need
   INSTANCE_VARS ||= [
-    :topic_view,
     :parent_post,
     :add_raw,
     :add_title,
@@ -490,12 +489,4 @@ private
     @post_actions ||= (@topic_view&.all_post_actions || {})[object.id]
   end
 
-  def post_custom_fields
-    @post_custom_fields ||= if @topic_view
-      (@topic_view.post_custom_fields || {})[object.id] || {}
-    else
-      object.custom_fields
-    end
-  end
-
 end