I don't know wether or not someone has said this before, but there is a flame god bug I have discovered.
When in flame god mode, you are invincible for a few soconds. If in this time you are hit by a Law misile, Flamed arrow or M79 grenade, you appear to have no health left. Once out of flame god mode, unless you are hit by another Law misile, Flamed arrow or M79 grenade (or land on instant kill platforms), you can't die. I belive this is a bug, and it proves quite annoying.

cool bug! gotta try it out! =D
the losing hp part happened to me.but no invincibility.

I have a bug where sometimes in the invincibility period, I will get hit by a nade and lose all but the smallest sliver of health. That leaves me with virtually nothing to play with once that 10 seconds is up. I think its the same here, only anything can kill me.

Interesting, it allways happens for me. If you pick up a health, then you can die though.

I can vouch that this has also happened to me, many times. I dont pick up the flamer much cus i suck with it but whenever i do this tends to happen. But im not invincible