wp_after_insert_post not working while adding new post

wp_after_insert_post is not working properly while adding new post. The $update parameter always returns true, despite adding new post.

do_action( ‘wp_after_insert_post’, int $post_id, WP_Post $post, bool $update, null|WP_Post $post_before )

UPDATE - here is the action

add_action( 'wp_after_insert_post', function( $post_id, $post, $update, $post_before ){
    if(get_post_type($post_id) == 'service' && $post->post_status == 'publish'){
        if($update){
            // Do something here, but $update is always true despite it is new post insert or update
        }

        $post_exist = $update ? false : true;
        if($post_exist){
            $product = wc_get_product(get_field('product', $post_id));
             foreach($product->get_available_variations() as $variation){
                wc_get_product($variation['variation_id'])->delete();
            }
        }
        $plans = get_field('plans', $post_id);
        $product = $post_exist ? wc_get_product(get_field('product', $post_id)) : create_service_product($post->post_title);
        $plan_names = [];
        if($plans){
            foreach($plans as $plan){
                $plan_names[] = $plan['name'];
            }
            $atts = [];
            $atts[] = create_attributes('plans', $plan_names);
            $product->set_attributes( $atts );
            $product->save();
            foreach($plans as $i => $plan){
                $var_id = create_variation( $product->get_id(), [ 'plans' => $plan['name'] ], $plan['price']);
                $row = [
                    'product_variation_id' => $var_id
                ];
                update_row('plans', $i + 1, $row);
            }
        }
        update_field('product', $product->get_id(), $post_id);
    }
}, 10, 4 );

If you are adding a post via the Dashboard, because WordPress creates revisions automatically, $update is going to always be true, even when you first publish the post.

One way to determine if this is a new post is to compare the post_date to the current day and time. Here is how I would do it inside your callback function:

$current_time = current_time('timestamp', true);  // no GMT offset
$publish_time = get_post_timestamp( $post_id );  // also, no GMT offset

if( ($current_time - $publish_time) < 30 ){
  // this post was published less than 30 seconds ago - it's new
}