Right wheel lose power

Recently my Rover can’t go straight by manual mode. Tested motor C and motor D in mission planner, always right wheel slow.
Changed motor driver and motor, it is same issue.
Finally I adjusted Servo1_trim parameter to let Rover goes straight by manual mode.
But it is not easy using this parameter, it still has problem in the case climb the hill.

Does it CubeBlack PWM hardware issue?

Can you share a log(.bin) if you do not mind?