Studio Theme Customizer not displaying content

I am updating my shopify site to use the Studio theme, and whenever I try to customize a page layout, it doesn’t actually show me what the content looks like on the page. I’ve attached a screenshot. You can see in the left column that I have images added into a Collage element, but on the right side it shows nothing being there. If I preview the entire site in another window, the content does show. However, it is impossible to me to preview any templates that I haven’t assigned to a page yet (which I don’t want to do until I have the entire new site ready to launch).

I have tried Chrome and Safari, and I’ve cleared cache and cookies and nothing is fixing it.

Other themes that I have in my library don’t seem to be having this issue.

Can anyone help?

Hi, thank you for your reply! How do I know what to check my store theme settings for? And how would I know if a third party app is causing the conflict?