This sounds like a new and interesting bug, then, thanks for letting me know.
Are you in an apartment or any special sort of world? My testing was in a basic one-level residential in Oasis Springs
Is it a regular residential lot? It looks like the devs added some extra checks to the vanilla vampire invasion situation to prevent it from happening on a small business lot, there may be a compatibility issue there. If it is a residential, which specific lot is it over there?
I think I've figured out the not-biting issue but I'd like to tackle whatever you're facing before I push out a fix
I tested on both residential lots near the Strangerville library and I can't replicate. Both Vlad and Lilith broke in just fine.
Vampires standing around can happen if they're the doorbell ringers and they're waiting to see if you'll let them in, or if there's a locked door in their way and the vampire can't route to you. I'm not sure what's happening in your case.
I will keep an eye out, though.