I dove into it a bit more, sorry for the double post.
The culprit seems to be the is_home function in the WP_Query class: https://developer.wordpress.org/reference/classes/wp_query/is_home/
This returns false, if I manually set it to true in the class, it does work.
I’m using a static (but completely empty) frontpage of which the content is set by using the GP Premium Elements module (I insert multiple shortcodes using the generate_before_main_content hook on the static frontpage).
Is there any way to ‘fix’ this?