Hi istandard,
I checked that specific post and it seems there is a problem saving the post to the database. I am not sure why this should happen but one point that might cause the issue is that you have one pretty long post all added into one section and the PHP object containing the section overflows.
I am not sure but there is an easy way to test. Please install the Post Duplicate plugin and clone that post and in the cloned one try to add new sections and move the element to those new sections.
By the way for me it shows the section and all the items and it is only not saving.


To make sure that we see the same thing, I suggest that you use the latest Chrome browser and clear the browser cache so we make sure that you also see the same thing.
Another point:
- Test for a plugin conflict. You can do this by deactivating all third-party plugins, and see if the problem remains. If it’s fixed, you’ll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.