1. build house 2. paint every surface with neutral paints (the ones with no environment effect) and use minimal decorations. 3. let sim walk around house What happens when the bug occurs? Sims in the house will get the "poorly decorated" moodlet (-1 or -2) in every room where they should be at 0 (not decorated) or higher.

There's a bug report for this issue If you ever come across a bug/glitch in game, go to that forum and search for it or add it yourself! That's where the Sims teams finds bugs to add to their Laundry List for game updates. .