Reproduce: If I make a maniphest task with mentions in it, then said person unsubscribes from the task, and I edit the task to say update the title or description, it resubscribes the person (presumably because they are still mentioned).

Especially in tasks with a lot of activity, I shouldn't have to do a full audit and remove the mentions, especially since they can still be informative. Obviously someone who unsubscribes doesn't want to be resubscribed without reason.

Versions: Upgraded to stable just this sunday.
phabricator c3bdcb4ca85487921909f0202aa760e8ed61404a (Sat, Feb 4)
arcanist 9503b941cc02be637d967bb50cfb25f852e071e4 (Jan 6 2017)
phutil 10963f771f118baa338aacd3172aaede695cde62 (Jan 13 2017)