I'm the one in the screenshot, and I noticed this effect from the OP's flashlight before - it's quite noticeable as long as the player holds the flashlight in their hands after turning it on. This bug does not seem to affect the headlamps in the game, and we've not been able to test weapon flashlights yet.

Had the same thing happen when switching from a 15'ish/20 M4 mag to a 10/10 one.