Why i getting blank user_activation_key in get_user_by( 'login', $login ) function?

I am facing strange issue, I have implemetned custom password reset template, Where I am checking key using

$user = check_password_reset_key($_REQUEST['key'], $_REQUEST['login']);

When i check in function detail and print $user = get_user_by( 'login', $login ); I get user object with blank activation key

WP_User Object
(
    [data] => stdClass Object
        (
            [ID] => 10118
            [user_login] => -----
            [user_pass] => ------
            [user_nicename] => j---
            [user_email] => jaysukh@---
            [user_url] => 
            [user_registered] => 2020-07-20 17:13:19
            [user_activation_key] =>
            [user_status] => 0
            [display_name] => jaysukh@----
        )

I can see user actiavtion key in users table and i can get it using SQL query $wpdb->get_results( "SELECT * FROM $wpdb->users WHERE id = 10455" )

Because of this issue, I am getting "Invalid key."

If any one has any clue how to fix this this would be much appreciated.

Many thanks,

Jaysukh