[GNC] Backup of Gnucash file shows incorrect reconciliation results

[John Dzielski]

Hi,
     I have been using GnuCash for many years.  I am not a sophisticated user, and primarily use it to keep track of my checking account.  I reconcile monthly, and once every few years I’m off by a few cents or dollars.  Today I reconciled the account and I was off by 70.10.  I unchecked every entry and stared at it for a while.  I think I may have exited reconciling, but not completed.  There were many c’s in the reconcile column.  I stared at the reconciliation for a while and found that there were two entries for 70.10.  I deleted one, and repeated the reconciliation.  I am not off by over $11,000.  I keep track of my Accounts.gnucash file with git, so I can recover the previous version from 2 weeks ago.  When I open that file, I see no c’s in the reconcile column.  When I repeat the reconciliation process, I am still getting an $11,000 error.  It seems something is being remembered.  I found some on-line threads that suggest that the previous balance is not correct, and that makes sense, but I don’t want to do something like that without some understanding of what happened.
    Can anybody tell me what might have happened and point me to a resource on how to fix it?  Thank you, John.