Undefined StdClass in shipping

Notice: Undefined property: stdClass::$weight in _uc_usps_package_products() (line 677 of /. . . /shipping/uc_usps/uc_usps.module).

Here is line 677 - I do not see the issue ($weight)

$packages[$key][0]->weight += $product->weight * $product->qty * uc_weight_conversion($product->weight_units, 'lb');