Win 10 Pro file uploads fail on wired connections

File uploads are failing on devices installed with Win 10 Pro when using a wired Internet connection.  This first became apparent when trying to attach files to messages in Gmail, so there is a thread on this topic in the Google support channel at:  https://support.google.com/mail/thread/170195914?hl=en

But the situation is definitely not limited to Gmail.  Using a tool like speedtest.net I have found that when my Win 10 Pro devices are connected to a wired Internet connection, the Upload test on speedtest.net returns 0.00 Mbps.

My devices are running Win 10 Pro, OS Build 19044.2006, Windows Feature Experience Pack 120.2212.4180.0.  

The problem is very repeatable.  On my Win 10 Pro laptop, using WiFi I'm able to attach files to Gmail messages or get good Upload times from speedtest.net.  But when I disable WiFi on the laptop and plug it into a wired connection, those type of file uploads fail.

To be clear, file synchronization tasks in OneDrive, Google Drive, Dropbox, etc. all seem to be working perfectly.  It is file uploading using a Web browser that consistently fails.  I've tested Chrome, Firefox, and Edge - all fail consistently when connected to a wired connection.  I've also tried disabling the firewall settings, and this has no effect on the failures.