I don't have the exact numbers for fertilizer, but I'm going to assume that it's a subset of those thousands.
With the decision to withdraw the most favoured nation tariff, there was an exception for goods in transit. Depending on when importers would have self-assessed the duties and on their understanding of how that provision for goods in transit was being administered, it's entirely possible that a company or an importer may have self-assessed the 35% duty and then realized subsequently that their goods actually were in transit, in which case that company would have sought a refund.
I'm not speaking to specifics here. That was a very common situation with respect to the timing right around March 2022. That would have been, potentially, a scenario in which a company would have self-assessed and then sought a refund afterward.