Okay... tank and healer queue for Elden Hollow I for the vet pledge...
Takes 1 hour to get a group when we get in the group, the group instantly disbands. This is an old bug that's been dogging the activity finder random queues for a LONG time - but never the specific dungeon queue finder.
Seconds later, we are pulled into Vaults of Madness Vet dungeon (we didn't queue for this) and we even get the random dungeon rewards at the end...