So I won't make this too long, my group cleared 16-man Veteran Monolith on Monday night at 11:30ish EST. The achievement is bugged, so we all filled out and submitted tickets as soon as we cleared.
Currently, we've had 2 or 3 members properly receive their achievements, one or two people who had support tell them that "Support unfortunately can't grant that achievement" which is a blatant lie, judging by the fact that SUPPORT HAS ALREADY GRANTED OTHER MEMBERS THE ACHIEVEMENT AND WE HAVE PROOF, and the rest of the tickets are still unresolved, despite the fact that we all submitted our tickets at nearly the same time.
My brain hurts.
Edit: Oh, not to mention the fact that another member had the achievement granted for 16-man SM instead of VM, so even when they grant the achievements it's not guaranteed they get it right. It seems most people are starting to get their achievements now though, it's getting there.