Our gateway only allows you to have a maximum refund matching the original capture amount (which is reasonable).
If you do an ad-hoc refund, it lowers the total amount of the refund available.
After you do a partial refund, is the main refund button on the order supposed to return the amount left from the capture or the original order amount?
Right now, it does not seem that the refund button works after an ad-hoc refund because the total refund would be more than the original capture.