This is a Custom Fields Issue - The Images are Disappearing

I have created a Custom Field that we have been using for well over a year, but now after I set up the fields, save the post, then visit the frontend, and come back into edit mode, I can no longer change/update the images in the CF area. They are still on the front end, but not the admin area. An update just occurred, so that might have something to do with it.

This is what I see before I add the images:

Here's what they look like after the images have been added:

And this is what I see after I have saved, gone to the frontend, and then back into edit mode.

Any help will be greatly appreciated.

Jon