While a friend of mine was farming Lo Pan, there's a glitch that 1) causes Lo Pan to not appear and 2) the skeletal minions keep showing up, making the part where you have to defeat all of them moot. After Lo Pan disappears they should have stopped appearing so the second phase of the battle could start. He had no choice but to flee and restart the battle since it would go infinitely otherwise thanks to the minions.

We don't know what causes it, he goes straight to Lo Pan and after he disappears the minions keep appearing, which prevent the battle from going. I hope KI can fix this so people don't suffer from endless battles anymore (just like the Hydra...).

I do not think that the flames themselves are the cause of the bosses from respawning properly. In fact, my friend hasn't used flames for Lo Pan and he got the glitch. And I remember when Katherine and I got the Ebon glitch and neither of us had the flames.

However, I believe that if you damage them too fast (like say, within a round from max health to the respawning point) it is possible that the glitch could happen, and the Blood Flames are certainly strong enough to cause that to happen.