[Gelöst] Custom HTML block looks different on one translated page

Background of the issue:
I'm trying to translate my English site into different languages using WPML. It worked for a Ukrainian translation perfectly, but I stumbled on German translation.

The original English page is versteckter Link.
The German example is versteckter Link,
The Ukrainian example is versteckter Link.

Symptoms:
On the German translated page, the custom HTML header block behaves differently. There is no video block under the title, even though the HTML block was copied precisely from the original page.

Questions:
Why does the custom HTML block look different on the German translated page?
What could cause this block to be missing on the German page?