I have a Garmin UT800 Front Light and Garmin Varia RTL Rear Light. The light network appears to form correctly, but intermittently when waking from sleep the UT800 is not controlled.
Both lights are in sleep mode at start, before I wake Edge 1040 from sleep.
The lights are found in the light network (see first screen image). But the front light is not being controlled, I have to manually change to flash setting using light switch. (see second screen image from lights menu). Putting back to sleep and waking again and both lights are controlled and detected properly on lights menu (third screen image).