I feel your pain as I am an accountant of over 40 years and 20 years a Certified Proadvisor in Quickbooks and QBO.  This is a ridiculous change.  It always used to keep the mapping from year to year and now someone has made a stupid decision to wipe the mapping each year.  I have always been able to go in and map new accounts if needed.  But now I have to go in and map ALL accounts again every year!  This is such a waste of my time.  I have an client with about 150 accounts on their chart of accounts and it takes me an hour to go through and make sure all accounts are mapped or not mapped. Most are needed every year!  I don't understand the "protection" that is provided by clearing the mapping.  We should be able to keep those and just add new mapping for new accounts.  If there is no one that needs a 1099 from accounts already mapped. It is OK!  It is not a mistake and not a problem. It is now the end of 2024 and Quickbooks has done nothing to fix this issue.  Again I am forced to map ALL the accounts for each of my clients again this year.  So frustrated.