Myself and a dps friend queued up and joined and killed the last boss and queued again to again be put on the last boss.
After wiping half a dozen times before the kill the first time (after the buff had built enough to heal the raid enough to survive the mechanics) I'm sorry but I shouldnt have to kill the boss again and hope again that I get a fresh instance so we both left ( I admit, making others join to the same fate).
My friend even messaged a gm who actually ticketed a GM who actually confirmed that no such preference exists.
I tried about 10 more queues before getting a fresh run that I finished early wednesday morning (EU) with the only one prior to that getting anything but the last boss. Sadly for me it was a bugged 2nd Twins where people had managed to get past the doors towards the last boss without killing the boss. Therefore the fight was in progress with nobody in the room to kill.
It was beyond annoying to have to queue alot of time and take the debuff or spend loads in repairs and time (probably more time than the 30 debuff) as others learn the last fight and build up the buff.
If Im honest I expected the boss to be nerfed last night so this problem would disappear, instead I just have to hope more gear and more experience will do improve things.