Autogen buildings are local data. You get the same buildings when offline as you do when online. The main difference seems to be (from my own limited testing) when online some data from the satellite image is used to colour the buildings.
Do you have the same issue if you follow the OP’s steps to reproduce it?
yes
Provide extra information to complete the original description of the issue:
Happened once today for me. Previously during the flight planing the ground textures on the world map gone completely white and after that loading the flight resulted in the scenery not loading (behavior described by OP) - a restart of the flight later resulted in an CTD during loading …
If relevant, provide additional screenshots/video:
unfortunately didn‘t screenshot the behavior, but it looked exactly as the screenshot from OP