A friend of mine keeps running into a bug when he uses the molotovs, if he moves after lighting it up but before he throws it he will get this everlasting small flame in the middle of the screen in front of his gun (I've seen it off to the left as well). this flame will stay there blocking his aim even after respawning and only a fresh game will solve the issue.
I also found this reddit post referencing the issue
https://www.reddit.com/r/insurgency/comments/a76rqp/anyone_else_experience_this_fire_glitch_that/
Thanks