Unusual reconciliation problem

All of my past reconciliations show in green (OK) except for the current one which shows a discrepancy of -$20.30, I have re-entered all transactions dates etc. several times and verify that they tally with my bank statement. Several attempts have been made to enter the said amount as a payment, but when next I try to reconcile it either shows the same discrepancy or changes all the past reconciliations to red (not reconciled)
I now notice that 5 previous reconciliations seem to be duplicated since the beginning of the year, all show the same date, account and amount with zero discrepancy.
I have reviewed other users comments and posts re reconciliations problems, but no solutions seem to be appropriate.

Just follow exactly to the letter the part in the guide on Unsuccessful reconciliation at https://www2.manager.io/guides/9235