My group completed vBDV with the full trifecta, killing all trash, etc., but didn't get the trifecta achievement or the dungeon nodeath, so it seems likely that the nodeath requirement is bugged. We trifecta'd it again straight after with the same result - no achievement. It's pretty unfortunate that you can put time into something like this just for it to bug out and not give it to you, and ZOS support just sent a generic response to my ticket saying to try it again, which we already did. We logged the dungeon and even did a nodeath Fungal Grotto 2 afterwards just to make sure it wasn't nodeath achievements in general. As you can see in the logs, there were no deaths the whole time:
https://www.esologs.com/reports/FcfaKNyWQJDTHLVC/#type=deaths&boss=-3&difficulty=0
For some reason the log is showing a wipe on the 2nd boss at 0% hp, but you can clearly see there are no deaths recorded there and it was actually a clear, not a weird 0% hp wipe.
Are nodeaths being buggy for anyone else?