That's right, you know the one. The 2 giant molten core-like mobs that are the first trash pulls before Ignis leave you with a fire bomb that ticks for damage and then jumps to another raid member. The debuff can't be bubbled/iceblocked off, and was intended to only be removed by the player who currently has the bomb running into the water around Ignis.
This is tough on healers during Ignis trash, since you have to clear the other 6 pulls while having the stupid thing bouncing around.
Exploit:
Have your raid stand near the teleporter after killing the 2 molten giants. The debuffed player should use the teleporter to teleport somewhere else. The bomb will immediately fly up high into the air and disappear into the sky trying to arc to the player. Have the player teleport back, and the bomb will expire in the air and you can continue with trash =)