I've had this problem occur to me a handful of times now, and I I have been able to reproduce it.   For some reason, when I zoom in on a city, seemingly by random, most of the city's tiles will suddenly disappear.

Example Image:

You can still mouse over some of the tiles, and even seem some effects, but you cannot see the tiles themselves.   And they just reappear after a handful of turns, sometimes as short as two or three turns, but once for twelve or thirteen turns.   Also, the tiles disappear off the cloth map too.

Example: