I am using Pixhawk 2.1 (Cube) running v1.7. The Pixhawk suddenly stops working (no radio link, no PWM signal, etc). I can switch it on and off, and flash it (even via QGC), but even after flashing the problem persists until a random time. Then it would work for again a while. I tried multiple things incl formatting SD card, cables, configurations, etc - but the problem doesn’t seem to go away and is also not specific to the hardware (similar experience with a different unit). It seems to work with v1.8,1, though. I am stunned because it just happened from one day to another without any changes in parameters, code, etc. Any clues?