In the latest blog post you say, "we updated Booking.com cancellations to always do refunds manually."
But when I go to Edit Booking.com Channel — Credit Card Payments, there is the Automatic option, which says, "If a credit card exists, automatically apply payments/refunds based on the cancellation policy you have configured in Booking.com."
So it seems that when I chose the Automatic option, refunds are still automatic. So I don't get what is supposed to be different.
That statement refers to alterations, which will still get payments or refunds automatically as appropriate if you're in automatic mode. For example, if the guest adds a day to a booking, the payment will be charged automatically. And if the guest removes a day from the booking, then that would be refunded automatically as well.
The difference is for cancellations -- that's the case where the refund will not be automatic, so you get a chance to be in the loop, so you'll need to go in and execute cancellation refunds manually.