specific post not found when permalinks set to postname

I have tried all the usual permalinks troubleshooting steps without success. Only changing the permalink structure or changing the post slug make a difference.

The post’s slug is “website-development”. With permalinks set to “Post name”, attempting to view this post using that slug results in a page not found error.

Changing the permalink structure to “Month and name” fixes the problem. This is not something we can live with.

Changing the post slug to “web-development” fixes the problem. We can live with this, but it’s not ideal.

Changing the post’s slug to “website-development-basics” fixes the problem. This is also something we can live with.

There is another post with a slug “website-development-steps”. Changing that post’s slug to “seven-website-development-steps” does not fix the problem with the first post.

There is a custom post type created with the Types plugin with a slug “website”. Disabling the Types plugin does not fix the problem.