The 4 tomestones

[Shioban]

Because they executed the "flaw" purposely. They knew what they were doing, they knew it was bugged, and instead of resetting the fight, they continued to kill a mob that was standing there doing absolutely nothing after deliberately setting it up to do absolutely nothing. That is exploiting. Cheating.

So you'd be a good little soldier and reset the fight?

Pfft, unlikely.