One of the VTOL motors didn't spin when armed and started to spin as usual after rebooting

Hi guys.

VTOL motors have been operating normal for many flights and one of them suddenly didn’t spin when armed. Also, it didn’t spin either when throttle was raised shortly for testing.

It started to spin normally when we reboot the system and VTOL could take off as usual but we are afraid it might happen again even in the air.

Please take a look at the LOG here.

There was no beeping sound from the motor at the time. and signal cable was firmly sitting in the servo rail when inspected afterwwards.

Thank you.