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.