I have a site built several years ago.
Everything works as expected except for the header. The header doesn’t load in Cornerstone and I have console errors in the browsers inspector. The header has an older classic ‘Content Area Off Canvas’ which I had to activate in the elements settings.
All pages and layouts appear to load fine.
Please note that I have cleared the browser cache, cleared the cornerstone ‘system cache’, there is no server or WordPress cache. I have also manually uploaded the theme again via FTP to ensure there wasn’t an upgrade issue.