No wiki button in repository

I have several private repositories. Upgraded to Pro to create a wiki before making public. Now 3 of my repos have the wiki button under the repository name, 2 do not? The missing wiki button is in the repo I want to add a wiki to. All docs I’ve seen assume wiki button is visible.

Compared the settings across the repos and cannot find any differences.

:wave: Welcome!

If you go into your repository settings, and scroll down, Wikis should be the first checkbox under Features.