Hi Rajesh,
thanks for your hints. I do as you wrote and cleared the cache, but it is the same. I tried different browsers, and the problem was different in the browsers.
The biggest problems are in firefox, it is as I wrote before.
A little bit better is Edge, there is only a small stumbling.
And fully finest runs Chrome – no problem.
It appears only in desktop-browsers, mobile is on all browsers fine.
Only posts are affected, all pages (and hompage too) are running fine.
Best wishes
Norbert