Right after cleanup is interrupted and your sim sets the plates down, pause the game for a few seconds. Make sure no other sims are near the sinks.
There may be a routing issue that causes your sim to stop. Credit: Drag and drop dishes closer to the sink. This may be a glitch that interrupts the cleaning. Check for dishes on half-walls or shelves. Most recently, I just kept giving the clean up command and eventually they cleaned the dishes. It may be a bug or it may just be a temporary glitch. had this issue as well but for me, it's not consistent.
