Camera trigger behaviour not consistent

I’m currently trying to accomplish an HITL simulation, stable 1.9 PX4 code, PixRacer r15, channels 1234 set for motors, channels 56 for camera trigger in GPIO mode (since i have to trigger an esternal camera with a simple pushbutton).

Camera trigger button in the camera settings work, “camera_trigger test” in nsh shell also.

Mission planned, set to trigger camera on the second and on the last waypoint (Take photo, single one, no mode selected, also tried with mode set to Camera, Video and Survey), but no changes on output pin 5 and 6 (checked with oscilloscope).

then, after the simulated mission (the drone fly correctly in gazebo) the button "camera trigger stops working.

Any ideas?