Can't override menu items

Problem/Motivation

NOTICE: PHP message: AssertionError: $url must be a string or object of type \Drupal\Core\Url in /var/www/html/web/core/lib/Drupal/Core/Template/TwigExtension.php on line 246 #0 /var/www/html/web/core/lib/Drupal/Core/Template/TwigExtension.php(246): assert(false, '$url must be a ...')

It seems to be coming from the menu_links() in twig or the macro_menu_links() in the compiled template.

Steps to reproduce

On a Vanilla Drupal 9.5.x

• Install component_library
• Navigate to home and click the override button on the top right of the toolbar
• Click on a menu link, for example Home
• In the override form modal, enter a name for the override and click on Save

This will fail with the AJAX error as documented above.

Proposed resolution

Implement an event subscriber that is able to replace URL variables in override templates.