Flight Modes Motor Behaviour

i have Holybro S500 V2 kit, with pixhawk 6c and during Stabilized and Position flight modes I encountered strange motor spin. Sometimes one motor just stop spinning or reduce rotation speed. Using Acro flight mode, it doesnt do it.

I tried recalibrate ESCs, recalibrate accelerometers, reflash autopilot but nothing works.
Also i am using Virtual Joystick in QGC. Also, Actuator Testing works well.

Anyone might suggest what could be wrong?

Check the min and max PWM values for each motor.