Page Navigation causes whole Page to "jump"

Clicking on the navigation arrows are making the whole page "jump" when the top edge of the H5P iframe is covered by the address bar of the browser, for example when scrolled down.

It has the whole page to jump way down. Its happening on wordppress as well as in the examples here: https://h5p.org/question-set

Just scroll down until the top edge is covered and then click on the arrow buttons. What could cause this behaviour? It seems to be related to anchor links on the buttons.