Garmin Fenix 7X PRO Sapphire Solar red light

Yes I’ve encountered that issue too. On all firmwares since release. 
also happens with the white light sometimes. 

Yes Ive noticed the bug...sometimes the white led's for me, they are dim while set at max... I go into the flashlight settings and just dim it then set if to full on again....

Has happened to me as well, twice that I remember. Once shortly after release about a year ago, and again maybe 6 months ago. Didn't think much of it, since it was easy to resolve just by turning it off and back on. I'm thinking the dim white light is some sort of bug where it stacks the brightness percentage twice on accident - like, it reduces it to 20% of current brightness, but it was already at 20% brightness, so it comes on at 4%. And maybe it happens with the red light (supposed to always be 100%) because it's still using the 20% brightness setting from the white light.

If I remember correctly, the times where it happened seems to have been the first time I use the flashlight after having restarted the watch or installed a firmware update.

I reported the same issue almost a year ago. In my case it went away with the resolution of solar charging freeze issue when during daylight condition tried to turn on the flashlight and the watch got hanged. No issues here.