[FIXED] Graphics Glitch - Disappearing Doors/Windows/Wall Objects
Create a room at ground level with an enclosed porch. Bump up the foundation and place stairs going up to the porch. Place doors, windows, etc. on front wall. See image here. Now, go up a level. The doors and windows will appear to have gone missing, with gaps left to indicate their position. The wall objects will have disappeared entirely. See image of this here. Go back to ground level, and everything will re-appear. Note that if the stairs aren't fully extended across the porch area, the glitch does not occur. Note that it doesn't matter whether you use fencing or walls to enclose the area; the glitch will occur either way.
Another example that I believe must be related is that this same issue occurs when objects are placed on a wall next to an adjacent roof at ground level. See image here. It does not happen on higher levels.