‘Duplicate’ slide will not save

OK so I have created the perfect ‘template’ for slides using the slide info on the right. I’ve successfully created 4. I’ll need 11 total.
When I am on the main master slider page and click ‘duplicate’ (copy slide), it creates a new copy no problem.
The problem arises when I go into said copy and make ANY edits – be it title, description, image, thumbnail – NOTHING saves. For instance, I’ll change the title of the slider first. I click save. I then go over to the other tab (main master slider page with list of slides), refresh the page and it’s still the ‘copy’ title, not the new title I just made. I have tried this method on all edits I need to make (title, images/thumbnails, descriptions for slide info) – nothing saves.

I end up deleting the duplicated slide and trying again. I’m trying to create all these slides without having to start from scratch for each one…why can’t I get anything to save?

I’ve tried multiple times, cleared my cache, etc