Your ejector spring is bound up and/or defective. Disassemble the bolt per TM and clean the ejector pin hole out. That may fix it; but I usually go ahead and replace the ejector spring when I do this because it is cheap to buy and replacing the ejector spring is a bit of a pain.
My guess is some of the sintered metal from the frangible rounds has found its way into the ejector pin hole and is binding it.
Your extractor appears to be holding and extracting, so likely not that or buffer or gas. Your bolt face is covered in tiny bits of metal, thus my guess.