After upgrade to 12.1.1 Decision box is appearing implying balances do not match bank account balanc

I wonder is the following a bug? We have recently upgraded to 12.1.1.

User creates NEW Bank Reconciliation and balance appears automatically and is correct.
User manually adds lines to the statement and then goes back and puts in control totals manually. They are correct and match.
User SAVES work.
Up pops a Decision Box:
"The following statement balances do not match the bank account balances previously entered for this date: Ledger Balance
Do you want to overwrite the existing bank account balances?"

Why does this appear?  It is happening for all currencies.

User puts in Yes - as they do match and then does the reconciliation.