Yes well, this is exactly why Xara's HTMLfilter now adds this on export:
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
On load a page will open at 1:1 zoom and be top/left.
This is one of the new features of version 8 for mobile support.
So maybe it's the browser on your phone which is not understanding this meta?.
I use Opera mobile.
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