Cash Refund transaction with Check selected as the Payment Method is designed to always post to Refunds Payable account when Create Check is enabled. Upon save, NetSuite automatically creates a separate Check transaction that clears that account.
On the saved Cash Refund (in View mode), users can click on the Check link under Primary Information section to view the actual Check record.
GL Impacts are as follows:
Debit to Sales (any appropriate Income account)
Credit to Refunds Payable
Debit to Refunds Payable
Credit to Cash (or any appropriate bank account selected in the Account field when the Cash Refund was processed)