WC_Order_item::get_id() return 0 inside woocommerce_checkout_order_processed hoo

Hi,

i was trying to loop throw order items and set some data in in order item meta along with some custom data insertion to a custom table with the snippet bellow.
but WC_Order_Item_Product::get_id() or WC_Order_Item::get_id() return zero.
also the items array key indicates that the line item is not saved.

add_action( 'woocommerce_checkout_order_processed', function( $order_id, $posted_data, $order ) {
	$order = wc_get_order( $order_id );
	$items = $order->get_items( 'line_item' );
	if ( ! empty( $items ) ) {
		foreach ( $items as $item_id => $item ) {
			// here i'm getting 0 return from the get_id method.
			$order_item_id = $item->get_id();
			// and also, the $item_id is new:line_items0
		}
	}
}, 100, 3 );

But if i use the woocommerce_before_thankyou hook then it works.