After shooting, for seconds - to maybe a minute, your muzzle flash in some instances stick around, and produce a light effect, showing where you shot/fired from, seconds - to a minute ago.
Really can give away your position, and is a game-breaking bug.
https://www.reddit.com/r/dayz/comments/a70d5q/be_mindful_when_you_fire_now_that_the_lighting/