Hello,
In first message you asked about white bg and not you changed it back to red..
Red bg is set for the active menu subitems and for the subitems on hover. Every of the menu subitems has the “current-menu” class http://prntscr.com/ppqrm3 so, theme applies styles for every menu subitem. We checked these menu subitems and found that this is a link to the same page that’s why you have that effect.