What is your installation folder's name?

I found out that having a dot "." in a folder name will cause those red question marks to appear, i.e. "GOG.com"

Installing in anything without a dot in a folder name, fix this issue for me. This is rather uncommon issue, but we had a few tittles before, where some special signs (#!%^*&) in a folder name, were breaking the game. There is nothing we could do, but to either block them, or inform our support about the issue. But we can't block every character :)

I hope that helps!

PS: Grid Cartographer is a cool software!