Not OP, but I have a litter robot 3 that is still going strong after 10 years, and a litter robot 4 that is around four years old. The only problem I've run into is occasionally the pinch sensor will get bits of litter stuck in it and I have to take the globe off and tap/push on the sensor housing, then it will allow cycling again.
Great machines!
https://www.litter-robot.com/