Servos with PWM on Ports 4, 6, 8 dosen't work


Hi out there. It tried a lot, and now I can say: Servos via PWM on Ports 4, 6, 8 (all on the front arm) don’t work.
If I run the same code with e.g. port 11, everything works fine.
I don’t think it’s the hardware, cause the original servo (or any other servos) are working fine on GP3 via control as R (J4).

So has anybody found a workaround for that? Otherwise, I have to rewire the ports on the mainboard to use the servo as an additional gripper.

Thank for any suggestions.