When laying down on a steep the camera clips through the ground and you able to look under the map and see above it.
See the screenshots.
Tested on 2 different location and one can be found at 087 036 on this map http://www.dayzdb.com/map/chernarusplus#5.085.037.
1: spawn on any steep hill
2: Face directly up the hill
3: press F5
4: Observe that you are able to see under the ground
Repro rate: 100% 2 different location 3/3 tries
Desired result: You shouldn't be able to see under the ground.
Game version: Stress test 18