At first I assumed the drive motor was at fault. Replacing the motor did not solve the problem. I luckily discovered a little black button on the motor which, when pressed, operated the ejection/refill cycle, enabling me to inspect the entire process. Upon ejection I noticed a bit of ice still adhering to the bottoms of the ice molds. This is what caused the overflow when it was automatically re-filled. Suspecting the tray mold surfaces were causing the ice to stick, I lightly coated them with cooking oil, after which the ice properly ejected and all was well for several cycles. Then the coating wore off and the problem returned. I ordered this new tray. When swapping it in, I noticed the new tray surfaces were highly polished whereas the old tray surfaces were very dull, probably from age and use. With the new tray installed, and after many cycles, it now performs like new.