Structure blocks will not save their contents

Steps to Reproduce

1. Play on Realms, creative mode
2. Place a lecturn or item frame or something that does a similar thing
3. Place something on the item frame, lecturn or whatever else
4. Remove the item on display on the lecturn or item frame etc...

Expected Results

The object is dropped after hitting the mine button

Observed Results

The item frame /  lecturn also gets deleted as well as dropping the object

This has been an issue on my realm for a while now and explanatory videos are on the way