I'd guess that Surface is sending headers that Server doesn't recognize as a real mobile device. Interesting that Public does.
Add ?:mobile=yes to the end of the string you are using to view the viz.
Might want to open up a case with technical support, too - so that dev is aware of this.
I knew of that - but it's not the same functionality of Public. On a touch windows device (even a laptop with a touch screen), the workbook/visual on public allows you to draw a box, select multiple, etc... It's not the gimped functionality of mobile.
I can get it to work that way on IE (-ms-touch-action) - that pretty much disables mouse events from bubbling up. Do it ignores the DOM and allows the interaction to pass through to the tableau viz.
I opened a case with support. Hopefully they can shed some light. There has to be others that have noticed this too.