I had a problem where some of my games in progress lost the picture of a map on game selection screen. They would start loading but hanged when there was one progression bar left of the loading. Because of this I reported couple games as broken.
I don't know what caused this to happen but luckily I got the solution for the problem. I got two challenges where the map screen was blank but still I tried to open them. Game informed me that I didn't have right map (number 10) and should go and download it. So I installed the map packs (first one wasn't right one) and got the mini-map back. So if you have lost mini-maps on game selection screen try to install them again.
And my version of the game is GMX boxed one updated with latest beta patch.

But the problem existed long before the beta update.