If you find the GL balance in the Bank Reconciliation screen in Cash Manager is incorrect, and it doesn't match the balance you are finding on the General Ledger Trial Balance report, you can fix it in Account History.
Note: As a precaution, please confirm a backup of the SL databases exist before proceeding.
Close all screens and reports, and click on the drop down at the top to click on initialize mode. Once initialize mode is checked, go into General Ledger and find the Account History screen. Put in the account, sub, ledger ID and year and tab off to pull up the data. Change one of the amounts in any of the fields, and save it, then change it back to the correct amount and resave. That should refresh the curyacct balance that shows the GL balance in Cash Manager Bank Reconciliation.