I have hypercache installed on all of my sites, but I have noticed frequently when I check a site with my mobile, all of the sites now and again lose their mobile look, instead of going to 1 column they go to 2, the normal laptop/desktop view. When I clear the cache manually and check my phone its back to mobile view. It is worrying me that people viewing my sites will forever get a non mobile friendly view. I have not changed any plugins for a while and only updates have been new posts. Has anyone had simiar? Can you help?