Some light sources cause a very ugly glare effect that does not look right. I will upload a screenshot and a video of where I have a chemlight lit and lit a fireplace on the floor of a house (convenient that this is possible since the indoor hearth does not work). I have seen this in the last few stress tests too but wasn't sure if it was specific to the halloween servers, now it is obvious it was not...

The road flare does not cause this as far as I can remember.