Yup, recent changes to discogs' API json output has broken pone's discog mod for good. I looked over pone mod and it is a rat's nest of regex's. Credit to pone for untangling that json mess from discogs. Despite liking regex myself, I'm not going dive in debug regex's other than my own. Sadly, this means that I had to retire my heavily modified discogs pone mod.
Afterwards, I modified @Florian's json-based discogs websource that comes with the mp3tag install (a mix between parsing discogs' json output for per track data and using regex for credits and notes information), some of which I shared here: Discogs (pone mod) no longer works - #10 by ms6676749
Unfortunately, my tag preferences deviate from pone mod a little bit.