Would it be possible for you to upload an effected build to the Gallery? For instance, the next time you encounter this problem, save the lot to your Library and then share it - call it roof test or something. Let me know here, and I will take a look in game to see if I can reproduce the problem. Before we take that step, however, I do want to verify whether or not you're using CC/mods. If so, please try removing them. You should also try clearing your cache and repairing the game. I know, it's a bit of a pain, but it helps to make sure we aren't dealing with an easily resolved glitch.
