Description

When editing specific lessons in a course, I encounter an issue where certain blocks do not display correctly in the backend, accompanied by the message: 'This block contains unexpected or invalid content.'

Step-by-step reproduction instructions

Please list the steps needed to reproduce the bug. For example:

1. Go to https://learn.wordpress.org/wp-admin/post.php?post=32842&action=edit
2. Scroll down to the examples where image hotspots have been used.

Please note, this is only one example but also happens with other blocks such as Flashcard block: https://learn.wordpress.org/wp-admin/post.php?post=32844&action=edit & even the Video block: https://learn.wordpress.org/wp-admin/post.php?post=12045&action=edit

Expected behaviour

The blocks appear correctly.

Actual behaviour

The block needs to be recovered and you see the message: 'This block contains unexpected or invalid content.' You can recover the block, but it appears incorrectly again when you refresh or return to the lesson at a later stage.

Screenshots or screen recording (optional)

Environment information

• Browser(s) are you seeing the problem on: Chrome
• Device you are using: Macbook Pro