Experiencing a timeout issue on the menu admin page. The page will start to load and then stall for a few minutes, ending in a ‘Page Unresponsive’ prompt. I have already debugged by disabled all plugins except Cornerstone while X Theme is active, and the issue is still present. The cache has been cleared. I tried downgrading the plugin and the theme versions, with no luck. We have also tried switching to different versions of PHP, all of which are listed as compatible in your docs. All other admin screens work fine except the menus screen.
Please note, the site is live and plugins had to be reactivated, but as noted before we have already tested disabling all of them and the issue remains.