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 ...
Ideas
Maybe you will find some more information in this thread
https://forums.ea.com/idea/the-sims-4-bug-reports-en/cl-du-fr-eco-objects-cluttering-worlds/5036144