I too have seen citizens refuse to enter buildings. Sounds like it might be the same bug as what is mentioned here:
I would say to the moderators to keep this bug report and don’t merge them, as this report only pertains to the door pathing / ghost workshop issue.
Interesting thought that is has to do with the doors. I have a building in a save that has two doors and they still will not enter the building (download link can be found in the linked post).