Description

Hey peeps

After upgrading to WordPress 5.9, my sites no longer HTML validate, but throws the validation error "Error: Element style not allowed as child of element body in this context"

For a more detailed error report, please see: https://validator.w3.org/nu/?showsource=yes&doc=https%3A%2F%2Fdev.oldrup.dk%2Fwp59%2Fsample-page%2F

These errors seem to be styling of blocks, given a dynamic .wp-container class, those being injected within the body tag:

These errors appear regardless of choice of theme.

Under WordPress 5.8 the sites validated flawlessly.

Could it be possible to store the styling in a CSS file instead, or somewhere else in the document, not provoking this error?

Please let me know if I can do anything to help troubleshooting this one.

Bjarne

Step-by-step reproduction instructions

To reproduce, create a new WP 5.9 installation, and validate the built-in sample page.

Test site available at: https://dev.oldrup.dk/wp59/sample-page/

Screenshots, screen recording, code snippet

No response

Environment info

WordPress 5.9. Any theme. No plugins.

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