I've checked the notification schemes and reporter is listed on all events so don't understand why the responses I make in an issue is not sent to certain reporters?
We have one case where no email have been sent and/or received from JSD to the reporter and one case where it has been sent and received to the reporter.
Attached the notification schemes as well which seems ok to my eyes 
The one that came trough to the reporter was when the reporter actually sent the issue from the start. The one that did not got an reply was an issue not sent in by the reporter ut I changed to the reporter I wanted to reply to afterwarrd in the issue, and the reply did not get trough...

Best regards Ash