Why do sticky posts (sometimes all, sometimes only some) show text beneath?

m4v3rick

For some reason sticky posts show the first post:

But if logged in only a few sticky posts show the first post.

Also it differs who is logged in. Some users see the first post of a discussion in the discussion list, some don't.

Flarum 1.6.3
PHP 8.1.16
MySQL 10.3.38-MariaDB-0+deb10u1

m4v3rick

Edit: You can close it. I tried a few things and found out that if you fully read the discussion, the first post won't be shown in the discussion list.