I did submit the above file to Xara Support.

I did further testing and found that files created from the first of June had problems. They produced errors in Windows 7 when opening them.

I suspect I originally edited and saved those files in my dropbox account using a new Laptop running Windows10. Those files published to my webpage had no errors when viewed in a browser. I took the Laptop back two days ago and got my money returned so I am unable to do any further testing.