One Drive files accessed through iPads 'Files' app do not automatically open the files associated app.

In setting up a new iPad Pro, I successfully configured One

Drive to work with the iPad (have many Excel files stored in One Drive from my Windows laptop).  Using iPads ‘Files’ app, I could see all of One Drives subdirectories and files and could click a file and see it automatically launch with the Excel app – all as expected. 

About a week ago something changed – Using iPads ‘Files’ app,

I can still see all of the One Drive subdirectories and files on the iPad as

expected, but when I click an Excel file it does not automatically open the

file in the Excel app, in fact nothing happens.

However, if I open the One Drive app first on the iPad, I can see the expected subdirectories and files structure and, when I click on a file, it will automatically launch Excel and open the file as expected.

Any thoughts as to why the ‘Files’ app is not recognizing a

file’s associated app and launching automatically, but, when the One Drive app is opened first on the iPad, files and their associated app behaves as expected?

Thanks