perhaps she thinks its better not to bother you by knocking and asking, when all you will do is say yes...?
we used to be irritated by kids in our street who would knock and ask if they could get their ball from the front garden, quite a few times a day - they had to walk past the ball to ask, and obviously we were going to say yes.
i know they were just being polite and they were good kids, but after a while we just said, no need to knock, just get it.
all are happy
do you think she is doing the same by just not wanting to keep bothering you with it?
also she is entitled to work on her building as much as she likes and obviously there is a problem if she keeps having it looked at, so maybe she figured she was saving you being interrupted...?