diff --git a/judge/signals.py b/judge/signals.py
index dfb2a54..d859e45 100644
--- a/judge/signals.py
+++ b/judge/signals.py
@@ -78,7 +78,7 @@ def profile_update(sender, instance, **kwargs):
         return
 
     cache.delete_many(
-        [make_template_fragment_key("user_about", (instance.id))]
+        [make_template_fragment_key("user_about", (instance.id,))]
         + [
             make_template_fragment_key("org_member_count", (org_id,))
             for org_id in instance.organizations.values_list("id", flat=True)
@@ -93,7 +93,7 @@ def contest_update(sender, instance, **kwargs):
 
     cache.delete_many(
         ["generated-meta-contest:%d" % instance.id]
-        + [make_template_fragment_key("contest_html", (instance.id))]
+        + [make_template_fragment_key("contest_html", (instance.id,))]
     )
 
 
@@ -127,8 +127,8 @@ def post_update(sender, instance, **kwargs):
             "blog_slug:%d" % instance.id,
             "blog_feed:%d" % instance.id,
         ]
+        + [make_template_fragment_key("post_content", (instance.id,))]
     )
-    cache.delete_many([make_template_fragment_key("post_content", (instance.id))])
 
 
 @receiver(post_delete, sender=Submission)
@@ -145,7 +145,7 @@ def contest_submission_delete(sender, instance, **kwargs):
 
 @receiver(post_save, sender=Organization)
 def organization_update(sender, instance, **kwargs):
-    cache.delete_many([make_template_fragment_key("organization_html", (instance.id))])
+    cache.delete_many([make_template_fragment_key("organization_html", (instance.id,))])
 
 
 _misc_config_i18n = [code for code, _ in settings.LANGUAGES]