Dear Xara...

If in a website design, I chose to add a % to the Page filename, that page will not render in Preview but will Export and Publish.
% is not a RFC 3986 reserved character but even if you don't want it used, you shouldn't let it be entered.
I was trying to use is for Percent-encoding.

Unfortunately, the offending page, accessed and tested within a NavBar, seems to crash Chrome.

Acorn