Error: The parent theme is missing (When activating child theme)

[bgardner]

Description

When trying to activate a child theme, I am seeing this error, even though the TT4 theme is there.

Error: The parent theme is missing. Please install the "twentytwentyfour" parent theme.

I first noticed this when a child theme was already active on a site of mine and then I updated to WordPress 6.5 Beta 1. In this case, it was a child theme of Powder.

Step-by-step reproduction instructions

1. Create a child theme.
2. Make sure parent is installed.
3. Try activating a child theme.

Screenshots, screen recording, code snippet

Screen.Recording.2024-02-14.at.12.50.57.PM.mp4

Environment info

WordPress 6.5 Beta 1 (Gutenberg active or not active)

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

[carolinan]

This is a duplicate of #58549
While I was not able to reproduce it two weeks ago, I can reproduce it today on 6.5-beta1-57630

[5AMsan]

I had the exact same issue and Site Editor was only rendering a black page. Deactivating Gutenberg on network and activating per site resolved.