When using mobile view, {{hat}} and {{collapse-top}} templates, and the content they enclose, are completely invisible.
Photograph of this revision of WP:AE displayed on a Samsung Galaxy S5 (I couldn't work out how to screenshot it!). Rendered in the latest version of Chrome for Android.
Screenshot of my sandbox page rendered in desktop view by Firefox 36.0.4.
Screenshot of the same page rendered in mobile view in the same browser. All sections are expanded and should be visible.