GVH v2.4 Basemap & Map Service Disappear - Handheld

When I access my Html5 v2.4 site using the handheld template, my bookmarks display the basemap and map service as expected. But as soon as I zoom in beyond a certain point, both the basemap and map service data completely disappears.

Although the tablet and desktop interfaces work properly, is there anything that I'm overlooking for the handheld environment that I should set to enable the basemap and map service data to display?

Walter