1. FPS Drop
2. Postern doors bug out
3. Dark Cloak / Shadowy Disguise
4. Dropping siege can cause your abilities to lock out until you hit escape
5. Getting stuck in keep walls
6. Client crashes
7. Emperor buff does not reapply after death
8. Passives can bug out after CC break
9. Logging in and not being able to target anything until you relog
Can't think of anymore at the moment, but I'm sure there's still a plethora I've missed.
So... in summary, what is the most deadly thing in Elder Scrolls Online AvA? Zenimax programmers.