It is hard to see but it looks like some form of delamination. If you made that blank, maybe the resin was already curing before you got to mixing them together? I am far from an expert here but that is my guess.
Or, is that wood where the blue is coming off of it? If so, I would guess that it was poor surface prep of the wood before pouring the acrylic (whomever made it).
Also, when it comes to turning blanks that are delicate, I always take it to my belt sander and round off all of the corners as much as I can before taking it to the lathe. It really helps prevent a lot of the grabbing.