Description

Testing revisions in both Templates and Template parts on a fresh install - it seems revisions aren't initialised by simple text edits (and saves) adding paragraphs.

The revisions button only appear after making a more involved edit (and save) like adding an image.

Step-by-step reproduction instructions

1. Start a fresh WordPress install with Gutenberg 15.2 installed and active.
2. Open the Site Editor and open a template or template part to edit.
3. Add a paragraph with text to the template and save the changes.

You can check for template revisions immediately, or after closing and re-opening the Site Editor. But none will appear.

4. Edit the template again and make a different change, like adding an image, and saving the changes.

After this edit - revisions will start showing.

Screenshots, screen recording, code snippet

Environment info

WP 6.1.1 and GB 15.2.2
No other installed plugins
Theme: TwentyTwentyThree

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