wp_get_current_user() returns ID 0 when called within custom class

Hi

Playing with custom reports code from here https://slimstat.freshdesk.com/support/solutions/articles/5000528531-how-do-i-add-my-own-custom-reports-to-slimstat-

I have added add_filter('slimstat_filter_pageview_stat', array( __CLASS__, 'my_function')); to public static function init() and then I have

public static function my_function( $_stat = array() ) {
        if ( $_stat[ 'resource' ] == '/somepage' ) {
            $current_user = wp_get_current_user();
            mail("[email protected]", "Slim Stat TEST", print_r($current_user, true)." ------ ".print_r($_stat, true) );
        }
        return $_stat;
    }

This will succesfully send me an email whenever somebody visits /somepage

When not logged in, wp_get_current_user will correctly return ID=0 but then when a user logs in, it still returns the same ID=0 as if no user were logged in.

Although the function itself is working, why is it not returning the logged in WP user info? Is this because the code is wrapped in custom class?

Thanks

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