Confusion around "Categories" sections on post

Hello, I have some confusion around 2 different areas for “Categories” in my post.

When I’m editing a post I can add and select a Category on the right hand side under “Document”.

When I preview my saved draft I see the selected Category at the top of the page (under the Logo), but not in the right sidebar under “Categories”. Instead, there it says “no categories”.

Perhaps the post has to be published before the category appears in the right sidebar?

I’ve included 2 screenshots. Thank you!

Hey there

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