This is similar to a problem I had before. When I add a picture to a templage page using Pagebuilder, all other parts of the page dissapear! It happens whether I use my own image or an image that came with the template.
I'm using the templage Corprex with Helix 3. The page I try to edit is the "About Us" page and the section is the "Person" secion at the bottom. I remove the place holder image "300x300" and replace it with a photo that is exactly 300x300 (really it doesn't matter which photo I try to place here, they all go blank).
Admin access supplied below so you can reproduce my issue.