The article is scant on details but from the description and the “shadow exchange” nomenclature it sounds awful like they’re uncovered a hawala exchange. It’s a system as old as money transfer.
Seems basically like must monetary instruments today. If I Venmo someone, no "money" is being transferred until they withdraw. We're using an intermediate broker to settle our debts, and it's very likely we'll just continue passing debt around people within that system without people withdrawing for some time.
Obligatory wiki link: https://en.wikipedia.org/wiki/Hawala