Updated Author of posts with Wordpress => Update Post module

I am trying to create a post and setting another UserID than the one in my Make.com API connector. I simply cannot make the post either get the author_id / “Author” value when using “Create a Post” or “Update a Post” with the Wordpress module.

What I am trying to achieve is update the author of a product (since that is a kind of vendor handling).

What could be the causes? I have tried both parsing and formatting the value and so on - and I can update a posts Title and Content, so it is solely the author / post_author I cannot make the Module update at all.

Anyone having success updating the Author from these modules, or does it seem like some kind of bug from the Module / API?