So I finished helping the people of Solitude, the Jarl gives me a housecarl, I enter Proudspire manor, and she attacks me. I can't even talk to her. Is it because I'm a vampire? Is it because I have Serona as a follower? She certainly didn't do that when I played as a werewolf. Also I have no bounty in Solitude (or anywhere else).

Could it be caused by a mod? I'm using AFT and an .esp that changes her looks (which I already tried disabling). I looked at the "crime" package using Creation Kit and the vampire box is not checked.

Is there some way to edit her so she doesn't attack?

what lv is your vampirism? are you a vampire lord? serana doesn't care if your a vampire. Others might.

Yes, I'm a Dawngaurd vampire lord (finished killing Harkon). But her behavior seems wrong.

I think you can use the setdisposition command.