I do know that Chase is switching some of their cards to a different physical format. I got a routine replacement Chase Slate MasterCard last week (that is my "alternate" card for places that take M/C but not Visa - there are some outside the U.S.) and it looked completely different than any credit card I have ever seen. It is the same size and approximate thickness, but my name and the card number are printed 90 degrees (that is, to read it you would have to hold it in portrait mode orientation) and they are not the standard-sized raised characters. They are smaller, and slightly raised, presumably to prevent alteration, but would not work with an old-style sliding sales slip imprinter. (I guess that means those are officially deprecated.) It also feels like it is a different plastic, with a matte finish.

It also has a touchless fast-pay chip in it. (This NOT a chip-and-PIN smart card, just the non-swipe proximity thing.)

So if the MP Select Visa cards are going to that format, there might be supply issues.