lib/pleroma/user_note.ex

@@ -31,7 +31,7 @@ def show(%User{} = source, %User{} = target) do
            UserNote
            |> where(source_id: ^source.id, target_id: ^target.id)
            |> Repo.one() do
-      note.comment
+      note.comment || ""
     else
       _ -> ""
     end