Notification after aditing a comment

Pre-conditions:
1.User1 and User2 are registered and logged in.
2.At least one branch is created.
3.The branch has a Code review.
4.User2 has permission EDIT_OTHER_POST.
5."Auto subscribe", "notify if private message is received" are turned on.
Step to reproduse.
1.User1 leaves a comment and subscribes on CR.
2.User2 edits this comment (from User1).
Expected result: User1 gets a notification on his email.
Actual result: User1 does not get a notification on his email.