While I was doing the heart event in lake doric in which players have to extinguish the fires, I faced a bug with burn stacks.
I went ahead and extinguished the fire, constantly in motion, also running through fire, sometimes even extinguishing two fire spots with one water bucket. I was about to leave the area when I noticed 5 burn stacks ticking on me, so I went ahead and cleansed them. However, the stacks were applied to me again (1 stack per second, up to 5 stacks) with no visible burning source.