Problem with login form

I’m having a problem with the login form for a site I’ve inherited, wherein only certain users are sent to the correct page after logging in. On this site, users with accounts are allowed into a special area. These accounts are all normal WordPress user accounts with very limited access.

In order to access this special area of the site, users must use a login form. The login form appears to be based on this code for customizing the wp-admin login:

if ( ! is_user_logged_in() ) { // Display WordPress login form:
    $args = array(  
        'redirect' => admin_url(),  
        'form_id' => 'loginform-custom',  
        'label_username' => __( 'Username custom text' ),  
        'label_password' => __( 'Password custom text' ),  
        'label_remember' => __( 'Remember Me custom text' ),  
        'label_log_in' => __( 'Log In custom text' ),  
        'remember' => true  
    );  

    wp_login_form( $args );  
} else { // If logged in:
    wp_loginout( home_url() ); // Display "Log Out" link.  
    echo " | ";  
    wp_register('', ''); // Display "Site Admin" link.  
}

from this page: https://codex.wordpress.org/Customizing_the_Login_Form

Just about everything works as you would expect. If you’re already logged in and click our login link, you’re kicked to /foo/. Problem is: if you’re not already logged in, upon logging in you’re still kicked to /foo/bar/. However, administrator accounts who log in here are correctly kicked to /foo/.

So far, I’ve run grep -rl "/foor/bar" /wordpress/site/path to find any remaining references to this path, but they are all just buttons and hyperlinks. I’m fairly new at this; is there something obvious I’m missing?