I have all three expansions and the game is fully patched. I'm Level 45 and thus far have had no issues fast traveling or porting through doors to new areas, with or without Serana in tow.
I'm stuck in Misty Grove with Sanguine. He transformed and engaged in dialogue as usual. He gives me the staff, then tries to send me back to...whereever. Crash to desktop. I've gone as far as three saves back...crash to desktop on the Sanguine teleport. With Serana parked elsewhere or with me...crash to desktop. My character is not vampire or werewolf or diseased to become a vampire.
The one difference from other playthroughs has been his starting location, but then, I just acquired the expansions so I assumed he switched locations due to those additions to the game. His starting point was no longer in the Riften bar, but in Ivarstead's bar instead.