Although, to be honest, not at all surprised by the actions of ChipMixer in this case. They have a pretty solid reputation for being fair and helpful. Excellent result for all concerned it would seem?
So the problem here is a problem during the operation of ChipMixer, right? And a lucky guy got some free money 
Obviously, ChipMixer's solution is really cool, but will it happen in the future? I don't know much about this technique, but how does this error occur?