Do you have this problem when the parent theme is activated on your site or with the child theme only?
Try to temporarily disable all third-party plugins, that do not come bundled with our theme – https://www.8theme.com/demo/docs/legenda/Plugins/Included_Plugins , and check then.
Let us know.
Provide us with temporary FTP access (not cPanel) – FTP host, FTP user, FTP pass. Due to the weekend, our technicians will be able to take a look at this problem from Monday.