My Sims always sit down before putting away dirty dishes and books. It now also happens on lots of other interactions.
The bug seems to be present with multiple interactions. Some cause it more often then others. I had it in my retail lot when trying to restock things or ring up customers. Also when I tried to write music. The Sim sat down before getting up again and taking out his guitar.
Please click me too on this thread if you have the issue:: [NEEDS SAVES] Routing/Sit down issue on several interactions.
EA/Maxis is still looking for save games for this issue.