Good news! Normally, the wire reads 0V. When I open the F-Cam app - no matter if the front or back camera is selected - it reads +12V. This is also the case when the reverse gear is selected, even when the F-Cam app is not opened.
Note that all of the above is working without having the reverse trigger wire connected to the reverse light positive; all through the CANbus system.
I’m going to change how my reverse camera is connected, as it right now only gets power when I select the reverse gear.