Bug with the translated posts?

Hello,

you can see on the link of the site I posted that the translated posts are shown in the overview, but when clicked on it, an error is displayed instead of the whole post.

All works fine with pages.

The problem persists with a different theme. The problem persists with all other plug-ins disabled.

My URL settings are: WP Permalinks: /%category%/%postname%/
Polylang URL settings: The language is set from content

The problem also occurs if I select: The language is set from the directory name in pretty permalinks

I hope someone can help me sort this thing out. Otherwise, it’s a great plug-in!

The page I need help with: [log in to see the link]