I fulfilled all requirements to upgrade my homebase to level 3 but could not enter the building in the home base where I can actually do the upgrade. After I returned from the north with J. Seed I still can't enter the building although my next mission is upgrading my home base to level 3. The doors to the house just won't open. Am I missing something or is it a bug?
I uploaded a screenshot: https://imgur.com/a/sgQhrAx
As you can see the main doors into the building are closed and won't open no matter what. Same goes for all the other doors into this building while all doors into the other buildings will open when being run against.