#3 - July 15, 2016, 1:23 a.m.
We've added a combat log line when Stealth breaks, and it should show what spell or ability caused Stealth to be removed. If you run into abilities that you feel shouldn't break Stealth and do, please create a bug report with the ability.
This is considered an 'Aura Dispel' in the combat log filter settings, so the easiest way to look for these is to create a new filter, and only have 'Done To: Me', and 'Aura' 'Dispels' selected.
...and yes, keep your eyes open for Demon Hunters :)