Some elements (like the search submit button) don't style correctly on mobile vBulletin.

Some mobile templates, like Metro, have no stylevars defined aside from image directories.  As a result, some of the adaptive styling values in AdminCP > Options > Threadloom may not render correctly on mobile.  An example of this is if your search submit button looks okay on desktop, but shows up as a white box on mobile.

To fix this, explicitly paste an RGB or hex color value in the adaptive styling field followed by the "!important".  So for the search submit button, for Secondary Color, you would entire something like "#0070AC !important".

You should now see the search submit button render properly on both desktop and mobile.