I was able to narrow it down: With cable and in idle mode if I’m carefully moving the headset without waking it up I can see that small movement on my monitor. That is not the case if I’m using wireless.
I tested the Trickster VR game wireless. -> When I’m moving the headset still in idle mode I can see that movement on my monitor.
For some reason in my game with wireless I can’t see any movement while in idle mode. It seams tracking is deactivated when in idle mode.
Is there any chance to control that tracking (on/off) in Unreal?