Hello Coco,
Thanks for asking. 
As you have tried out the solutions, please make sure that you are using the latest version of X Theme and Cornerstone or Pro theme i.e Pro 2.1.6, X 6.1.6, Cornerstone 3.1.6. We have released a new update that contain bug fixes, please take a look at the changelog and kindly update the same.
https://theme.co/changelog/
If problem is still there, please share website login details in a secure note for us to take a closer look. Along with that please give us to the permission to troubleshoot the problem. We may have to perform some tests on the website which may effect the performance, appearance, layout and functioning of website temporarily.
Thanks.