Hello and thank you for the quick feedback,
I had tried to create a pen for this problem, however the error appears only on the live site with Wordpress and DIVI (Theme).
What I see in the meantime is that the page is bigger after the reload than when it was first loaded.
This causes the animation to display correctly after the reload.
However, I have not been able to figure out what elements it is and how to prevent it.
If anyone has any ideas about this, it would help me a lot.
However, the error is of course not in GSAP in particular.
Greetings
Carsten