Jetpack Related Posts appear on some posts but on others not

That’s funny. Jetpack related posts do show on one post:
https://www.mygoal.de/lass-uns-mal-wieder-joggen-gehen/
but not another:
https://www.mygoal.de/der-jahrestrainingsplan-im-ausdauersport/

I already compared both posts whether there are any custom settings, fields oder templates. But there are not.

Does anyone have an idea or “similar posts” ?? ?

Sorry ,if you have to scroll over long German texts. The site is about endurance training and thats what we practice in writing too.