diff --git a/app/serializers/activitypub/note_serializer.rb b/app/serializers/activitypub/note_serializer.rb
index abaf29047ad390d3805a3025e343bdaee9bca5ff..ddafb540d0a2d5c0fbbae97e7d5201448f67a8ae 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 67da92cd5ce40846faeee1c55a21e05e8269851d..fe3dc9bfcfb2838d9bd1a75437f13d2cbe57e374 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