Cover block with background image not working with style variation

[juanfra]

Description

While working on TT5 and the latest Gutenberg, I noticed that some of our patterns were suddenly not working correctly.

I started checking the issue and apparently when you have a group block using section styles, and a cover block inside the image is not being shown. I saw that there were some recent changes to the z-index of the cover block, so it might be related.

Step-by-step reproduction instructions

1. Install a theme that uses style variations on groups (Like Twenty Twenty-Five)
2. Create a page.
3. Add a group block, pick a different section style than default.
4. Add a cover block inside the group block.
5. Add a background image for the cover block.
6. Confirm that the image is only displayed when the group block has the default variation. For all the others, the image won't show.

Screenshots, screen recording, code snippet

Screen.Recording.2024-10-11.at.16.11.03.mov

Environment info

• WordPress 6.7-beta2
• Gutenberg trunk
• TT5 trunk

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

[renatho]

@juanfra, thanks for reporting it quickly! I reverted the original solution and implemented a different one. All details in the PR: #66074.

[ndiego]

I have added the related issues/PRs to the 6.7 project board. cc @getdave @kevin940726

[juanfra]

This one can be marked as done, the changes that introduced the bug have been reverted here.

Thank you all! 🚀