Reserve America is just a processor.
What did the credit card statement was the vendor making the charge? The last time I used RA, the card was charged by the state park department.
And refunds are made to the credit card charged for the reservation.
Another possibility may be that the number of refunds being processed is stressing the RA system.
As for your last question - a reservation is not booked until the CC company acknowledges the funds are being held for payment to the vendor.
A refund sometimes takes the credit card company longer to process. They are setup to send you money out, not take it in.
My COE cancellations refunds were approved by the Recreation.gov contractor, and did not show up in my Amex account for about three days. Amex wants the money 'in hand' before they will credit me.