You may see duplicate payments to Brex on your QuickBooks Online account if you have added your bank to the QBO bank feed and are also using the QBO Categorize & Match Receipts
This is because the payments to Brex pulled from the bank feed will typically have the date that the payment left your bank account, whereas the payment to Brex pushed from the Brex dashboard will have the date that it reached Brex's bank account. Because of this date discrepancy, the payments will not auto-match. To rectify this, please follow these steps:
Step 1: Go to the Banking tab on QBO and find the payment to Brex
Step 2: Click on the payment, and click on Find Match
QBO will suggest the payment to Brex that is duplicated for the same amount so that you are able to match these.