Coincidentally I have had problems with my Pyrocat HD which I have not used for a while. Searching the APUG archives gave me a place to start.
Mixing new solution B gave no improvement. Next was to mix new solution A.
Having read the start of this thread, I was less than confident when I saw that my Pyrocatchetol (sourced in the UK) has the same appearance with different coloured flakes.
Nevertheless I went ahead and am very glad that I did. The developer worked as it should despite the rather unsightly appearance of the Pyrocatchetol. I have now processed 14 sheets of Acros 5x4 which are all fine.
It took less time to mix up 100ml of Solution A than read and post to this thread!