Design > Styles: this post type (undefined) does not support the author

[carolinan]

Description

In classic themes, if you go to Appearance > Design > Styles, the author and author name blocks are present in the preview, but they do not work.
The message that display is:
"This post type (undefined) does not support the author"

In block themes, if you go to Appearance > Editor > Styles and select the author block from the list of blocks, the same message shows.

Step-by-step reproduction instructions

See above.

Screenshots, screen recording, code snippet

Classic theme:

Block theme:

Environment info

No response

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

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

[im3dabasia]

Thank you @carolinan for reporting this issue , I can confirm in Classic theme and Block theme, the Author and Author Name block are undefined

Classic theme

Block theme

[Mamaduka]

This is a recent change see #67136.

It looks like Appearance > Editor > Styles doesn't populate the postId and postType context, while Editor > Styles sidebar > Stylebook does.

Screenshot