It’s a combination of multiple errors. Read up on how binary or hex values work.
0x31 Would be a combination of
ERROR_INVALID_STATE = 0x01, //<! an invalid state was requested
ERROR_BRAKE_RESISTOR_DISARMED = 0x10, //<! the brake resistor was unexpectedly disarmed
ERROR_MOTOR_DISARMED = 0x20, //<! the motor was unexpectedly disarmed
It’s my guess, but I think it’s the only way to explain it.