diff --git a/lib/pleroma/web/activity_pub/activity_pub.ex b/lib/pleroma/web/activity_pub/activity_pub.ex
index adb42b9ab..96b774c21 100644
--- a/lib/pleroma/web/activity_pub/activity_pub.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub.ex
@@ -309,7 +309,7 @@ def unfollow(follower, followed, activity_id \\ nil, local \\ true) do
 
   def delete(%Object{data: %{"id" => id, "actor" => actor}} = object, local \\ true) do
     user = User.get_cached_by_ap_id(actor)
-    to = object.data["to"] || [] ++ object.data["cc"] || []
+    to = (object.data["to"] || []) ++ (object.data["cc"] || [])
 
     data = %{
       "type" => "Delete",