Guild Wars 2

I’m not sure whether this is a bug or I imagine it or I am missing some invulnerability which doesn’t let me use cloak and dagger on oppenents.
But it happens that often lately that I think it’s weird. Sometimes CnD works, other times it doesn’t – was running through a thief (while using CnD) and a necro who likely were all out of useful skills as they were nearly downed and got no stealth, my log doesn’t list any skills that would buff them and the third guy, whatever the class, was long downed. I don’t think they had a trap as they were capping one of our towers and were likely out of supply. Same happened with some mesmer clones (can they be buffed?) and a lot of other classes all in “open field” (to explain whether or not they could’ve used a stealth trap) – but randomly – so is it me or is it a bug?
Edit: And I wasn’t revealed.

Edit: I think I know what the problem is, I unchecked autotarget, so I might be targetting different stuff while trying to hit the guy in front of me. So: dismiss unless you have an advise for me how to solve the targetting mess.

Edit³: No, I still have autotargeting and it still happens mostly with enemy players in wvw though.