wrong pages showing in navigation, some mp3 players not showing

For some time now a website I maintain has been unstable. On some browsers, when the site appears some wrong pages appear in the main navigation and on one page the mp3 players don’t appear (whereas they do appear on other pages.

One page in particular I deleted and made a new page to appear in the navigation but initially the old page appears in the navigation even though it is deleted. On refreshing the browser the old navigation still appears.

I’ve tried disabling all the plugins and reintroducing them one by one, but it doesn’t solve the problem. I’ve tried changing the theme but again it doesn’t solve it.

I am using a child theme of the Admired Theme