I've seen other players talk about some of the festivals (like the spice festival and the flea market) stacking on top of one another so that when you attend one, all the objects from both are still there and cluttering up the space, making it totally unplayable.
Well, in my game it happens with all the festivals. They never clear out. Even when you go to visit the lot during a time when no festival is taking place, there's still clutter there as though a festival should be taking place.
I noticed it began after I installed the For Rent expansion pack. Nothing seemed amiss at first. But I had a sim living in an apartment near one of the festivals and had that sim move out of their apartment. Then I realized that the sims inventory included market stalls, tables, and trash cans from the festival area, all of which were debug items that are unusable, so I don't know how they ended up in the inventory. Shortly after that occurred, then the glitches with the festivals started taking place.
I play on a PC and have no ccs or mods and didn't activate any cheats when making the move. So I don't know how this could occur apart from a direct glitch between my game and the For Rent expansion pack. Likely conflicting with the City Living expansion alone, since no other glitches have occurred elsewhere.