In Full-Site-Editing, edits made to the code in a template part are not showing

It’s probably because you made edits in the site editor which created a template/template_part post in the database, and that’s what’s being used, not your original HTML.

Unlike PHP templates, the HTML files in a block theme are the starting points. Once a user makes changes/additions those changes are saved in the database and take precedence. You would need to export those changes back to HTML files and replace the ones in your theme with the new versions, or delete the posts in the site editor.

It’s generally best to use the site editor to make your changes, not the raw HTML. Some blocks may start to fail block validation if you deviate too much, and user changes might cause data loss when your changes don’t map to anything a block normally generates. Lots of custom HTML blocks also makes your theme unintuitive and difficult to work with.

From what I can tell this is the precedence order:

  • DB user template for current active theme
  • HTML template file in child theme
  • HTML template file in parent theme
  • PHP template in child theme
  • PHP template in parent theme

Do confirm this though as I’m not 100%