PWM_MAINX_TRIM is resetting after reboot

Instead of setting physically sometimes we need to use PWM_MAINX_TRIM parameters to level the servos. If I’m not wrong in v1.11.3 and further versions it was working perfectly. Now with v1.13.3 after rebooting autopilot servos move to its previous position but the PWM_MAINX_TRIM parameters have the value which we changed to it. How can we prevent the servos to go previous position? Any idea?