I don't think that there is any possibility that this is a GoCardless problem. They act on information sent out by QBO. The payment requests were sent out a day early. The most likely explanation is that the DueDate flags on the invoices were set wrongly. This is the third occurrence in just over 2 months for which the timing of processes has apparently gone wrong. I could speculate about the reasons why this is happening but what matters to users is that it gets fixed soon.