Backlight won't turn on during Running profile

Is the gesture option enabled?

https://www8.garmin.com/manuals/webhelp/forerunner945/EN-US/GUID-C9A5E731-8826-4AD0-8087-F6E2EAC625D6.html

Yes its enabled - 'during activity' and set to 'on'

Odd.  I have mine gesture set to After Sunset so that the backlight's not active when I don't need it.  I also have the brightness set to 50%.  In my opinion, the sapphire lens (Fenix 6) needs a little more backlighting than the standard lens.

So during the day, you don't have it working, only at night?

Correct

So nothing to add if my gesture is not working?

I assume the backlight works when manually operated?  Otherwise, I've got nothing else.

Do you run late at night or early in the morning? Your watch may be set to Do Not Disturb during your normal sleep hours, which will disable backlight alerts, nav alerts, etc.

During an activity, hold Light to access the controls menu and see if DND (crescent moon icon) is green. If so, select it and toggle it off. (At least that's how it works for 935.)

Hey, yes the backlight works manually and also the gesture is turned on for 'out of activity' and works fine. I just noticed, as I haven't ran at night yet, that if I start an activity after dark, the tilt gesture is working...but I've got it set to 'during activity' not 'after dark'....so annoying....