Hello,
Please clear all cache and check how the site looks then.
Temporarily disable cache plugin and “Menu cache” (in Theme Options) do required changes and activate the cache after finishing changes.
If the problem on the single product page will be solved after disabling the cache plugin http://prntscr.com/mputv6 – check minification options to find out which one causes the issue (HTML, CSS or JS or few of them).
Regards