Incredible that Isaacman, as the NASA Administrator, took the time and effort to respond so transparently to a reporter on X.
Not an expert so I can't really comment on this. But hopefully NASA will soon.
I am hesitant to get ahead of a proper data review, but I understand the space community’s curiosity, especially when imagery can give the impression of a problem.
As you would expect, engineers were eager to inspect the heat shield, starting with diver imagery shortly after splashdown and continuing with the review aboard the ship. No unexpected conditions were observed. I suspect when the images are released, it will be pretty obvious the stark difference between Artemis I and Artemis II head shield performance.
As to the question specifically, the discoloration was not liberated material. The white color observed corresponds to the compression pad area and is consistent with the local geometry, AVCOAT byproducts, and transitional heating environments. We observed this behavior in arc jet testing and expected it in this compression pad area.
We will complete a full data review across all systems, including the thermal protection system, and make the results publicly available.