Yesterday, I switched from being a healer to dps and when my friend tried to queue us up for a random dungeon, he got an error message because we were both listed as healers. That's an awesome feature to prevent from having multiple healers or tanks in a random dungeon.
Well, today, I queued up as tank to do a random dungeon and noticed someone else had a sword and board. I checked the group tab and realized we had 2 dps and 2 tanks.
This was not possible to do yesterday so I'm assuming when you fixed it to where multiple people couldn't queue up as all the roles (thank you for that btw), it now allows people of the same role to queue up for the same dungeon.
Luckily, during my random dungeon, no one died and the dps burned the enemies really fast but this could be a potential problem for veteran dungeons. I would hate for someone to get vFL or vRoM with 2 tanks, healer, and dps. That calls for a bad time.
I attached a screenshot to prove that we had 2 tanks for the random dungeon.