For me, everything is as it should be - operating instructions say that if the suction is not good, it stops - but with 'beep' and LED display. Happens if it is too wet (window or microfaster) or too dirty, or if there is a power cut.

No, this has never happened to me. I have already cleaned many windows, both small and very large ones. The robot always goes back and forth and from top to bottom. It then stops as described.