If you stated on the Recovery Rebate Credit Section that you did not receive one or both of the Economic Impact Payments, but it came after you filed your return, then IRS would have examined your return and reduced your refund by that check amount. This could be a big difference in your refund and make it almost be cut in half in that situation but it might still be correctly handled by IRS.
Please review your return copy and the letter IRS will send you regarding the "adjustment of your refund" and see if they match