@CircuitD Is this issue present when you play other Sims? Is it present in another game save?
Perhaps you would be willing to move the entire Mods folder to the desktop and remove the mentioned cache file (as in the directions provided above) but then re-open the game and do not enter any of the game saves you already have but make a brand new game save in the game (this way it will be fully 'vanilla' with no Mods active and no possible affects from any)... Then if you enter and play in that game save for a while do you see the same issue occurring? Once you have confirmed one way or the other you can leave the game without saving.