A File with the same name as the folder published as _index.md AND with a permalink

Correct: Sidebar Navigation shows an “Overview” für this page

Bug: The sidebar navigation entry for this page contains an incorrect link reference. Instead of pointing to the configured permalink (test-perma-folder-link), the navigation system references a non-existent page URL. Users clicking the sidebar entry will encounter a 404 error or be directed to an invalid destination. The issue appears to stem from the navigation generator not recognizing the permalink configuration in the page’s frontmatter, defaulting instead to a URL that does not exist in the site structure.