I'm reluctant to speak for them from memory, so I'd do a search at bladeforums for their comments. I know that Josh had posted a question to Nate after some issues that he, (Nate), had with a batch of MagnaCut which resulted in the knives not being up to his standard. As I recall, it wasn't a matter of performance, but cosmetic...at least for the most part. The matter went up the chain to both Peters on the heat treat end, and Niagra on the steel itself.
There was some resolution, which I cannot discuss...but whatever was for public consumption might be found on the forums.