diff --git a/app/serializers/activitypub/note_serializer.rb b/app/serializers/activitypub/note_serializer.rb
index abaf29047a..ddafb540d0 100644
--- a/app/serializers/activitypub/note_serializer.rb
+++ b/app/serializers/activitypub/note_serializer.rb
@@ -57,7 +57,7 @@ class ActivityPub::NoteSerializer < ActiveModel::Serializer
   end
 
   def virtual_tags
-    object.mentions.order(:id) + object.tags + object.emojis
+    object.mentions.to_a.sort_by(&:id) + object.tags + object.emojis
   end
 
   def atom_uri
diff --git a/app/serializers/rest/status_serializer.rb b/app/serializers/rest/status_serializer.rb
index 67da92cd5c..fe3dc9bfcf 100644
--- a/app/serializers/rest/status_serializer.rb
+++ b/app/serializers/rest/status_serializer.rb
@@ -87,7 +87,7 @@ class REST::StatusSerializer < ActiveModel::Serializer
   end
 
   def ordered_mentions
-    object.mentions.order(:id)
+    object.mentions.to_a.sort_by(&:id)
   end
 
   class ApplicationSerializer < ActiveModel::Serializer