Ravana's fire everywhere, forever

Hi! Twice now I've done the Ravana trial. Both times it's taken two attempts, and more to the point, both times on the second attempt the graphic effect for the ring of fire AoE has "stuck" and stayed the entire fight (which makes it pretty confusing from that point forward, I might add.) Additionally, the last time this happened I was pretty horrified to go home to a private cottage and find the floor of it also on fire. :D

Win 7 Ultimate, DX11, Radeon HD 6800 series GPU

http://i.imgur.com/cSys131.png

http://i.imgur.com/ax6CTpT.png