Hi! I have nearly the same problem as a closed one 8 days ago and as I’m no native speaker I copied some text over - sorry 
I require your help regarding a problem I’m encountering.
Litter-Robot III Connect: blue led starts blinking after some single cycles.
Did the following : Litter-Robot III Open Air - Blue Blinking Light but this would not fix anything.
What I did and recognised in the process, in this order:
- Removed the drawer. Unpluggued for 10 sec. Pluggued and Still have blue led blinking constantly.
- Start a cycle with the drawer removed, than cancle the cycle: Still blinking.
- Cleaned with damp cloth the DFI lens which is hard to reach as it’s a single sensor in the small recess of the clear plastik. Now after a cycle the blue LED stays on constant. But after <24h it starts flashing again, while the drawer isn’t full at all an nothing is sticking in the sensors way.
- I noted that the sensor design seems to have changed. While the old design seen on youtube and pictures is a 4 LED sender on one side and a receiver on the other side of the drawer, my one has only one circuit board on the side with the buttons. The other side has the clear plastik cover, but is not populated. Might be problem related or not?
Hardware concerned :
Litter-Robot III Connect
Product Code: RB-Ltr-122
Additional information :
Invoice #926909 (ordered 2019-11-26)
I would be glad for any hint!