Description

On sites using a classic theme, Duotone filters apply in the post editor, but don't appear on the live site

Step-by-step reproduction instructions

1. Activate a classic theme such as Twenty Twenty One
2. Open a new post and add an image block
3. Add a duotone filter to the image
   • (observe that this filter appears in the editor)
4. Save and view the post
   • (observe that the filter does not appear on the live site)

Screenshots, screen recording, code snippet

Inspecting the image block shows wp-duotone-rgb10400-rgb255232232-1, even though the filter is not applied.

Environment info

• WP 6.3.1
• GB 16.5.1

Deactivating Gutenberg altogether allows the Duotone filter to appear on the live site.

Possibly related? #49293 (I can't tell if this is the same issue - it appears to just be about the default colors available, and not the function of duotone on the live site).

Many WordPress.com customers have reported this issue; those reports are being tracked here: Automattic/wp-calypso#78442

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