I found something quite interesting, there's this girl (Don't mind the weight, all the failed snacks had to go somewhere lol) 
She's been living with me since the release of the update, but when I checked on another town recently, I found this
In that town she's actually living with me too, it's not the only town where it happens, but there's also one or two towns where she doesn't even know me and I don't have her contact and is still working at the care home, all I can guess as to how is that she was an assistant since before the update and back then all towns shared the care assistants between them, so now different instances of the same girl exist as different characters.
From what I checked and remember, a few other girls also had this happen, I actually don't know how it would be possible to fix this or if they count as the same girl actually, it's really curious.
Edit: Alright, I just confirmed they are different characters, at least with the one who doesn't know me. I sent her to the facility just to try and now they both appear in my first town, one in home and the other at the facility.