What is the ruling on an assignment of debt (Huwalah) when the underlying sale contract is subsequently rescinded after the assignee has paid the debt?

Primary text

If a buyer assigns the seller's claim for the price onto a third party (the assignee), and the assignee pays the price, the assignee is absolved of liability if the buyer subsequently rescinds the sale due to a defect, mutual agreement, or a dispute regarding the price. The buyer reverts to having a claim against the original seller. This is because the assignee paid with the buyer's permission.