Don't know if anyone would have time to fix this bug but just quoting it for reference:
My quad (PikoBLX, Inconceivable#2126) uses flip-reverse as Pos.1 flight mode, I am using SyncPWM (not DSHOT) for reverse rotation.
After running autotune, with the battery still connected to the quad and TX radio still active (flightmode 2 and disarmed) I've plugged the USB cable. As I was waiting for the usual 'new autotune detected' wizzard, the motors started at full throttle in reverse.
I presume that for whatever reason, the GCS sent throttle zero to all outputs (which is full reverse when using bi-directionnal syncPWM).
No big deal as the quad was siting flat on the table and full reverse just converted it into an overpowered suction pump (so the beast was basically stuck on the table). I was glad it happened with the mini-owl as disconnecting the battery with rotating props could have been a challenge without the propeller guards!