Not yet, having trouble understanding what could be going on.
GP uses media queries for the mobile responsive aspects of the site, which is the same as practically every other responsive site on the internet. So this issue wouldn’t just be with GP, it would be will millions of website.
I tried searching for “MobiTab media queries” but nothing came up at all, so people haven’t been searching for it.
Have you tried on other GP sites? Our demo for example? http://demo.generatepress.com