I've had the problem in 1.8 where a map in an itemframe would disappear, but logging out and back in again would cause it to appear again and braking the block that it was placed on would cause it the block to drop, followed a a second or so that by the map and item frame.

However, I've just opened this 1.8 world in 15w32b and all the maps on itemframes in my map room have disappeared. They don't seem to reappear when I break the blocks. See the two images