I was in Azjol Nerub earlier and Hadronox was bugging out. After the first crusher died, the other 2 despawned after pulling. I dropped the group because the healer was being an abusive asshat, but in the future is there a workaround? I checked the bug tracker and it seems to be something that’s had an open report for a year but the staff can’t replicate consistently.
It is possible to run down with the flow of enemies and just skip him if that happens. Jump down the hole. The big ones respawn after a short" while so it is possible to try again.