Hello HankRand,
Welcome to the Microsoft community.
I understand how annoying this current situation is. But to better help you, I would like to know if you are changing this Excel file in your PC and saving it, will it sync properly to OneDrive and not report an error?
I would like to suggest you create a new Excel sheet to test it. Upload the created file to OneDrive, then make the changes in your iPad and see if the same problem occurs.
If the problem does not occur with the newly created file, then it is likely that there is a problem with the original Excel file itself, and you can try copying the contents of the original file into the new document and see if there is still a problem.
Alternatively, if the problem does not occur after you change the content in your PC, it is also likely that there is a problem with the OneDrive for iPad application itself. In this case, you can use OneDrive's feedback channel to give feedback on this issue. Microsoft takes every issue from users very seriously and the development team will review the submitted feedback regularly.
If there's anything that's not clear, don't hesitate to let me know.
Sincerely
Mavis - MSFT | Microsoft Community Support Specialist