No images loading via Visual Editor

A client is attempting to use the visual editor tool to add a new image to their page but unfortunately when they select to add an image nothing is loading.
I have managed to replicate the issue with the following steps.

• Load: https://admin.siteglide.com/#/site/727769/cms/pages/40915
• Open visual editor
• Select image to replace
• Click image button to replace
• Observe no images are shown in images folder
  If you compare this to the images folder inside the Assets category on the same instance you will see there are many images within the build.