Panorama 6 file names change when saving to a folder in iCloud

I recently started using iCloud to store files in my “Documents” folder. After opening and changing a file I use to keep track of expenditures in my checking and credit card accounts, I saw that the file name had changed from Accounts 19 to Accounts 20 and that the changes I made only appeared in a new file called Accounts 20.b - a backup file. Two other new files with names consisting only of capital letters also appeared spontaneously.
(I’m running High Sierra on a 2015 MacBook Pro.)
Apple senior tech support staff were completely baffled and concurred with my proposal to remove folder containing Pan files from the cloud.
Has anyone else encountered this problem? What did you do?