In the latest 4.7.14 version, the template core > front > global > siteSocialProfiles was changed to add support for X (former Twitter) share link, but the <LI> element was mistakenly changed to an <A> element instead.   4.7.13 version: <li class='cUserNav_icon'> 4.7.14 version: <a class='cUserNav_icon'>   You can easily compare it in the Theme Differences tool, too: https://invisioncommunity.com/index.php?app=core&module=system&