KK2.1.5 QuadCptr X Config. uncommanded two motors stopped (mot 1 and 2 frwd. motors)

[acsrandd]

I have approx. 13 flights on this quad. X Pattern configuration (HW Ver. KK 2.1.5 v, FW Ver. 1.1981 Pro Steveis). Shortly after liftoff while hovering at approx. 30 ft. the two forward motors stopped! Post-crash these motor run with no issue. It is like the FC interpreted a command to fly forward at max. speed (or something akin to this), but my Tx sticks were set at hover. Post-crash no issue with the Rx / ESCs or Motors! Anyone else experiencing anomalous behavior i.e. sudden uncommanded change in flight.

Post Crash Readings from KK 2.1.5 FC:
Sensor Test:all OK
ACC Calibration: Performs Cal. OK
Debug
GyroRollZero: 505
GyroPitchZero: 509
GyroYawZero: 513
accXzero: 506
accYzero: 507
accZzero: 642
ESClowlim: 448
BatAlarmvolt: 428
ServoFilter: 39
VectorX: 00000000
VectorY: 00000000
VectorZ: 00000000
Accangleroll: 1
Accanglepitch: 1
BatteryVoltage: 485
Vectorlen: 00FFFFFF