This happened to me as well after installing the 4.7 patches. First it messed up all my assets (they were almost all gone!) and I had to load everything as I was playing. I then re-downloaded assets (400MB+) through settings, and a few troops ended up with these corrupted images.
Yesterday, I decided to uninstall the game and re-install it with fresh asset downloads. Still have corrupted images. I know for sure Fist of Zorn is messed up.