The page template for most pages in the system is html_page.xml for the specific device. The template for CMS pages, however, is view.content, and this can cause the pages to output differently for each device. So the device type template could be entirely incompatible with the CMS site.
The workaround is to turn off the script and properties that recognize devices, but this breaks the tablet and mobile clients. The two should work together.
Related Problem: PRB589116