If the quest is just rewinding when you're having sex with her, that's a bug, no worries. Though I think it SHOULD be fixed in the most recent version. Maybe. If not, it's definitely fixed in the next one.
But fixed or not, you're not really missing out on anything. Her story is still incomplete and that's pretty much as far as I've managed to get her. More will come, but I've got a million other things I want to work on as well :D