diff --git a/app/activitypub/routes.py b/app/activitypub/routes.py
index 3b6523ae..fab4bb1a 100644
--- a/app/activitypub/routes.py
+++ b/app/activitypub/routes.py
@@ -564,7 +564,7 @@ def process_inbox_request(request_json, activitypublog_id, ip_address):
                                 community.subscriptions_count += 1
                                 db.session.commit()
                                 activity_log.result = 'success'
-                                cache.delete_memoized(community_membership, user, community)
+                                cache.delete_memoized('community_membership', user, community)
 
                 elif request_json['type'] == 'Undo':
                     if request_json['object']['type'] == 'Follow':  # Unsubscribe from a community
@@ -582,6 +582,7 @@ def process_inbox_request(request_json, activitypublog_id, ip_address):
                             if join_request:
                                 db.session.delete(join_request)
                             db.session.commit()
+                            cache.delete_memoized('community_membership', user, community)
                             activity_log.result = 'success'
                     elif request_json['object']['type'] == 'Like':  # Undoing an upvote or downvote
                         activity_log.activity_type = request_json['object']['type']