WordPress 5.8: Image Compare Block Not Working in Site Editor

[bizanimesh]

I have:

• WordPress Version: 5.8-beta4
• Jetpack Version: 9.9-beta-983222196-g76ef471
• Gutenberg plugin installed
• Jurassic Ninja site

Steps to reproduce the issue

1. Go to WP Admin area and click Site Editor from the left sidebar.

2. Add Image Compare Block.

As you will add the block, you will see this error: This block has encountered an error and cannot be previewed.

I got the same error with WordPress Image Block also. Nothing changes even if I deactivated the Jetpack plugin. I'm not sure if the error is coming from WordPress.

One more thing to notice is: You will not get the same above error if you will try adding Image Compare or Image Blocks by going to Posts > All Posts > Edit or Add New post in WP Admin.

Let me know if more information needed!

[bizanimesh]

Primary issue: #19654

[jeherve]

Thanks for the report. Closing this as a duplicate of #20184, where we're tracking this issue.