As a sentinel myself, the only thing I remotely agree with is the force stasis comment. If it weren't for that comment I would say that this post is hilarious, but that one made me think it might be for realz...and that made me sad
Every classes CC does this. Its because of the way animations play, if an ability has a long animation or is uninterruptable, it will play out and look like the target is not stunned for a second, but in reality the ability has already done damage on the server side and your target is stunned, or they will finish their uninterruptable attack and then go into the stun animation.
You can also resist most stuns, and while rare, it does happen.
And then there is the resolve bar. If its full, your stun isnt going to work.