Thank you for the report - this one is currently by design.
When using a standalone VR headset (like the Quest 2, without external tracking station), there are 2 mouse options. The first is the standard one, and the other is a virtual mouse which follow the head tracking permanently. So, like the VR controllers, you can’t catch an object outside the VR FOV with a mouse. If you turn your head, then move the mouse, it iss “transferred” on the “actual screen” which is necessarily in the actual FOV.
The only way to manipulate a knob, or a lever in VR with the mouse (impossible with a button, as you inevitably give an input with the mouse from the movement) is to select it before turning the head. For example, you can look straight, hover and click on the throttle lever, turn your head to the left, then apply power to the throttle, it will work as intended. If you have just hover the throttle, once you’re head is turned, you can’t click the throttle and apply power.