Ok so I played through the Beta as a Vampire Lord and I started a Kajiit, werewolf, Dawnguard named Kaj, (ran out of names...as if I ever have any) and I played for 1 day to level 10 and joined the Dawnguard. I was lvl 13 rescued Serana went to Castle Volkihar and saved right before Lord Harkon transformed. I wanted to see if I could use the "Ring of Hircine" as a Vampire Lord to be a hybrid. It didn't work so I reloaded. That's when it bugged.
Reload Attempts:
1. The first reload I did Lord Harkon transformed and he didn't talk to me, his cape was glitching and all that. So I said "Well this is weird"
2. I reloaded again and he talked to me, everything looked ok and when I declined his offer he said. "So be it! You are prey, like all mortals. I bannish you!" and he hopped into the air and got the conjuration spell ready. He didn't cast it so I wasn't bannished. So I was stuck in Castle Volkihar.
3. 3rd attempt and it was the same as 2 except the conjuration spell didn't even appear in his hand.
4. Same as 3rd
5. 6. 7. & 8. All the same as 3.
I got mad and deleted the character.

ha

ouch that svcks.

at least it was only a low level character.

yep lucky it didn't happen on my level 64 character with daedric armor who is a werewolf that was going to be a Vampire Lord.

Thats what you get for trying to become some type of lame hybrid.

finish MG and let serena turn you into one it may work then.