Where is this function being run? I don’t see it triggered by any load handlers or timeline actions.
This does not occur in the .hype document.
You can start to identify the root of the problem by choose to “Inspect Element” on the white space.
There you will see that your iframe has a height of 8000px:
<iframe style="border:none;" frameborder="0" width="100%" height="8000px" src="https://www.lovcour.com/wp-content/uploads/sites/2/hypeanimations/26/index.html"></iframe>
But your iPhone layout has a height of 7500px. So that’s probably the difference.