this is too odd dude !!
i think i know whats going on but, emm...
maybe it's an excessive script check and reading problem, i mean...
emmm... you gave 2 conditions in a way that the fps creator from his computer read and check it in a excessive speed and repetitions, using a odd amount of memory and using alot from the cpu, causing the lag, and comsequently hiding the fire decal, by the drop of framerate.
it happens alot with me, but, in bigger scripts ya know ?
it is a ridiculously crazy theory, but if the scrip was bigger it could have muth more sence
mods for creating a inteligent game,at least