We are facing an issue in BRS, i.e. bank transaction amount is matching but reconciled amount not matching and OB is showing as total reconciled amount not an OB.

I offer you a warm welcome in the Community, @sangeetha-k-firs. I'll share insight on the reconciliation process in QuickBooks Online (QBO).

Here are the common causes for ending balance issues:

• An incorrect ending balance was entered at the beginning of reconciliation.
• Missing or duplicate transactions.
• Transactions entered in QBO that haven't cleared your bank yet.

The first things to check are your opening and beginning balances. The opening balance is for those accounts you reconcile for the first time. On the other hand, the beginning balance is for those accounts you reconciled in the past. If the amount is correct, proceed to the next steps below. 

Ensure that the ending balance is correct. Here's how:

1. When you're in the Reconciliation window, tap Edit info.
2. Check the Ending balance and Ending date.
3. Refer to your bank statement, and make changes if necessary. 
4. Hit Save when done.

Check out this article for additional information: Fix issues at the end of a reconciliation in QuickBooks Online. Proceed to Step 3 if you're still having issues at this point. 

Also, here's an article that lists things to take note of about reconciliation: Tips for year-end reconciliation. 

Tag me in a comment below if you have other questions about the reconciliation process in QBO. I'll be sure to take care of your concerns. Have a great day ahead!