Adding a code block in collapsible block causes page to not be editable

[Rock-HOG]

Describe the Bug

I added a collapsible block with a code block inside. When I save the page and go back to edit, I see nothing in the editor. I'm using the new WYSIWYG. I have tested this multiple times in other books, and the same thing happened.

Steps to Reproduce

1. Create a new page
2. Add Title
3. Add Collapsible Block
4. Expand Collapsible Block
5. Add Code Block
6. Save Code Block
7. Save Page
8. Edit Page

Expected Behaviour

You should be able to add a code block to a collapsible block and then edit the page in the future.

Screenshots or Additional Context

Browser Details

Microsoft Edge on Windows 11, Google Chrome on Windows 11, Firefox on Windows 11

Exact BookStack Version

24.12.1

[ssddanbrown]

Thanks @Rock-HOG, I've added this to the megathread: #5245