Excel files on iCloud Drive get renamed to random 8-character name

I've seen a couple of posts on this. I have an Excel file on iCloud Drive that is sync'd across a couple of Windows computers. When I make changes to the file, periodically it will keep the temporary filename (8-character, random name such as "E8C27C00", and the actual Excel filename is deleted. This temporary file can be renamed to the original ".xlsx" filename and will then continue to function as normal.

I just started noticing this behavior after changing my cloud service from OneDrive to iCloud Drive, so pretty sure the problem lies with the iCloud Drive synchronization.

I have noticed that it seems to happen in one specific way - if I attempt to close Excel by clicking the "X" in the upper-right corner and then "Save" from the pop-up window, about half the time the above rename will take place. If I first manually save the file after changes and then exit Excel, I have not seen the file get renamed.

Does anyone have a permanent solution or is this something that Apple needs to take a look at? How can I request support for the iCloud Drive Windows application?