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.
Yeah, I've always had two or three cats using them, they like to use them as an opportunity to hide and pounce on one another as one exits the litter robot globe, inside the globe they have a pretty limited field of view.
Great machines!
https://www.litter-robot.com/