CC is not reliable at all in M+ right now
I don't know what's going on with uncontrollable damage sources this season, but it's been a pain trying to CC anything in a dungeon.
In the image you have 2 examples of CC breaks by random damage on mobs that were CCed before we were even in combat, and they are broken by the proc of xenas' rings, or my eyes from the diabolist hero talent, while not targeted at all by anyone.
Warlock demon apex talent is also absurdly broken and will target whatever is in range and in combat, after multiple fixes from blizzard about their targeting. Here you have a clip in a pit of saron where the fire lady just start blasting a random paralyzed mob in narnia (bonus points for the shit interrupt design of this class preventing me from interrupting the cast).
https://medal.tv/games/world-of-warcraft/clips/mJoMIlg6L6HjXIzqr?invite=cr-MSxUZ1YsNDM3OTE3NzEw&v=17