Someone mentioned Esfand’s random MC reset in this thread, which is a pretty clean example of the other end of the spectrum. In that case, they just turned up to raid and the instance had been reset. They didn’t do anything intentional to cause it or go looking for reproduction steps so they could abuse it - in fact, they reported it to us and didn’t continue until they got confirmation that it was out of their control (and that we wouldn’t consider it an exploit if they cleared).
Side note for the curious: that was a completely separate bug that has existed since 2004, and actually happened several times back then, it just wasn’t being broadcast to thousands of viewers at the time.
The raid reset bug is an entirely different bug with no known reproduction steps. The instance layering exploit only applied to dungeons.