LED on servo - problem


I don’t know if anyone has had a similar problem.
I am running a simple 6 pin LED on 3 servo outputs (RGB).
The 3 5V wires are on the R+ G+ B+ pins, the 3 PWM wires are on the R- G- B-.
It works nicely from a Lua script (and also from MAVLINK), but only if I used the previous motor before it on that servo. The LED control works for a short time, then stops. I need to transfer it to the motor servos to get it working again.
I do not change any settings on the autopilot (Pixhawk 6C - I/O PWM Out). In the Mission Planner servo settings, I can see that the script is working, but it is not being realized on the servo.