I've never had this happen before - I've built a room very near the bottom of the bottom of the map, and every time I log out, some (but not all) objects in one of my rooms have moved slightly along the Z axis. Only certain objects seem to throw problems, and only some of the time. Usually objects that were stacked on top of something else.
Is the problem that I'm building too low on the map? Should I be building closer to the actual base rooms? I've tried grid vs no grid, but with no luck. Are there anyways to fix this problem, or at least make sure it breaks reliably?