neprostoman wrote:

Hello everyone! I've found a workaround for this bug - you need to enact Communal Rites choice in the Religious Rites civic and start "Procession" action in the city. It forces a tile reload on the troubled city and cures the visual glitch.

Not gonna lie, was a bit skeptical but it actually works. It doesn't work 100%, some districts refuse to show up, roads and rails mostly remain unaffected, and it is basically a hail mary that works sometimes, but it doesnt fix the grey textures under the districts, unfortunately. Still, it is good to know it is not entirely hopeless.

Also, another "workaround" for this is playing with less competitors in big maps. The number that seems to work best for me and my 16gb ram, 4gb vram, 20gb pagefile, is 5 competitors. Only by the late game the roads started to get buggy. But not always. 6 competitors it eventually happens, 7 or more it always makes districts invisible. I just increased pagefile according to this thread and will test it tomorrow and report back soon.

neprostoman wrote:

Hello everyone! I've found a workaround for this bug - you need to enact Communal Rites choice in the Religious Rites civic and start "Procession" action in the city. It forces a tile reload on the troubled city and cures the visual glitch.

Thank you, Neprostoman. Procession resolves the issue.

A bit late but I had the same issue but couldn't use procession due to my religion being Atheism in late game.

However when I went to war with another empire it did manage to fix the graphical glitch and all my affected tiles returned back to normal. Must be due to the fact that the war screen doing something with the tile colors outside of a designated battlefield but it worked this way for me