iCloud Drive changes the name and removes extension of Excel file

I have an Excel file stored on my iCloud drive that I update frequently (2 or 3 times per week) on Windows.

I have been doing this for several years without any issue but this week, when I tried to open the file using the Windows Explorer recent files list, I got an error saying that the file could not be found.

So I went to the location where the file is located and saw that the file had changed name and its extension was removed. Was "Financial Follow-Up.xslx" and it got changed to several uppercase letters and numbers without extension. Something like "554BFE00". I changed the name back to what it should be and also added the extension and the file opened without issues.

Now this is happening everytime I save the file.

And it is only happening on this file on iCloud Drive.

Any clues on what's happening?

Thank you.