im pretty sure the flame appears when other people who are on the essence of light quest go near it, since in essence of light you need to interact with the flame several times. i dont think they made it "instanced" in the sense of only THAT person can see it. I think that's the bug part in that it just shouldn't show up for you at all if you're on united as one, but it would when triggered by somebody else on essence of light that comes in the vicinity of it, then it disappears after a short period of time, probably some game code that auto hides it but doesn't do it fast enough, hence the bug. this is the reason I think it would randomly spawn during certain times, and it spawned for people without ever even changing channels so i think that sort of throws away the idea (not entirely of course) of changing channels to "spawn" it. although it could be 2 ways to spawn it.