Definitely not my intent to slam the previous oil, but @High Performance Lubricants uses both esters and AN's in their formulas, which have a reputation for cleaning. It's quite possible that they've dissolved some deposits in the engine in which this material was suspended and they've now made their way into the filter.
I wouldn't worry about the metal flakes unless your engine starts burning oil then you have a problem for sure. My little brother is picking up a brand new Tundra Platinum in a few days. He feels the Tundra engines are great.