For the past couple of weeks, there are some Intrepid Adventures (Hammerfall) that are bugged, where you cannot complete the instance.

The Adventure that I see this happen the most of is where you have to kill some Cephalords (I think that's their name), and then so many Minions. The problem is that you can kill Minions all day long, and they will not count.

This doesn't happen all the time, but it is annoying and you cannot complete it.