When using the code you provided, it shows information for the post author user.
I can return the post author (and current user) ID just fine, but when it’s supposed to be appended like the_field('state', 'user_' . $other_user_id ); it doesn’t seem to work. If I change ‘user_’ to any user ID in use (i.e. ‘user_3’), it returns the right information in that field.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users