When I start getting unexplainable glitches like that I always try deleting caches and restarting. Sometimes it's a false memory issue, (Not sim memory, game memory) like when old house shadows remain after you bulldoze them. Of course, it's good that you found the real culprit though. The tip about checking cheats is helpful too. Constrainfloorelevation can make all sorts of mess if you forget to turn it on again.