Filter dynamic drop down not working

I created the function for this form:

function wpf_dynamic_choices_categories( $args, $field, $form_id ) {
     
    // For field #10 in form #851, only show entries in category #37
    if ( '1551' == $form_id && '2' == $field[ 'id' ] ) {
 
        $args[ 'category' ] = '34';
 
    } 
     
    return $args;
     
}
 
add_filter( 'wpforms_dynamic_choice_post_type_args', 'wpf_dynamic_choices_categories', 10, 3 );

to show all however, my list is empty after I apply the filter, what happen?