I have had the same issue - although, in addition to an excessive amount of the cubes spawning in my inventory, my sims also seem to be bugged out by the Neighborhood Action Plans. As an example - during the week that an exercise action plan is put into effect, my sims will abruptly stop what I have instructed them to do (study for a particular class, stop writing letters of recommendation etc) so that they can do pushups. It all seems to be related, and none of these bugs occurred prior to Eco Lifestyle. I read one of the replies that said if you invite someone over, choose the option to modify them in cas effectively switching household control, that it could be causing the bug. I play between several households that are all intertwined, and do that often. As suggested, I marked the household as unplayed and attempted all of the activities mentioned above again, with the same results.
In addition to alllllllllll of that - Lumps of Clay continuously spawn in my sims inventory and around the lot they live on. When visitors come over, they are holding Lumps of Clay. I never want to see another Lump of Clay or Future Cube again.
These are quite irritating bugs and are significant enough to make gameplay much less enjoyable.
