It has the same limitations as cloak so I think any DOT or AOE will break it and once it is gone it is gone. no need to crouch but crouching will put you into regular stealth (hopefully). any action that breaks cloak will break invisibility. unless they have detect or revealing magelight they will never see it even if you are right on them. you can jump but not sprint combine it with a speed effect if you need an escape.