Issue Summary

The notification is not been sent to the '@' mentioned users in the issue comment if the user making the mention lacks the global permission for "Browse Users and Groups."

Steps to Reproduce

1. Remove a user from the global permission for "Browse Users and Groups."
2. The removed user can now '@' mention some other user in comment.

Expected Results

1. The users list should be listed when the user types in '@'. 
2. The mentioned notification should be sent to the mentioned user

Actual Results

1. The user appears to be able to mention other users but no notification is sent to the person being mentioned.

Workaround

As of now, the only way is to assign the Browse Users and Groups global permission to the user.