Algol Plus Ltd

// must fill $_POST
add_action( 'woocommerce_checkout_phone_order_processed', function ( $order_id, $checkout_data, $order ) {
  if ( class_exists( "AtumMultiInventory\Models\Inventory" ) ) {
    $oi_inventory_qty = array();

    foreach ( $order->get_items() as $item ) {
      $inventories = array();
      foreach ( AtumMultiInventory\Models\Inventory::get_order_item_inventories( $item->get_id() ) as $inventory ) {
        $inventories[ $inventory->inventory_id ] = $inventory->qty;
      }
      $oi_inventory_qty[ $item->get_id() ] = $inventories;
    }

    $_POST['oi_inventory_qty'] = $oi_inventory_qty;
  }
}, 10, 3 );