I haven't seen any official confirmation that it's fixed, but I myself haven't had the problem since installing the most recent patch. My best advice is to start a new file in a town with combined rabbitholes, have your sim(s) get jobs in them, and see for yourself.
EDIT: So I went on the patch 1.55 and apparently missed Rica's response to my own statement about combined rabbitholes being fixed in my game:
Edit: Well - Joe MacDuff needs to go to a presidential debate and it's not an option. Felicity MacDuff needs to do a ballet recital and can't. Jules MacDuff was trying to work on some bridge and it's not there.
Still bugged.
So it's still pretty much bugged.
However, that doesn't mean that the dynasty can't be completed in a town with combined rabbitholes. Rhoxi and Tiamet were able to do it. It's just more difficult.