Problem with the "startpage" to change the sidebar

Hi,

we have different sidebars for different pages. Everything works very well. Only with the “startpage” we have problems.

We have a special sidebar for the startpage. We have also set these under “Choose a custom Sidebar for this entry.”

Unfortunately, the sidebar does not change – no matter what we set here.

For example: If you visit the startpage https://phototravellers.de/, there is a different sidebar (Über uns) than on https://phototravellers.de/sehenswurdigkeiten-amsterdam-these-orte-muss-man-sehen/.

But: In the backend are exactly the same settings!

We can not find the mistake. Can someone help us?

best regards
Florian