The full text of the notice is actually :
Notice
 
International FedEx fulfillments allow only one package. If more than one package is required, please break up the shipment into multiple fulfillments of one package each.

This is a notice, according to the informational screen, however, IMHO it is also a major, major bug, and here is why:

On a web order, a customer places an order, and shipping is calculated in real time rates.  So, for example, on an international order, real time rate is calculated at $75.34, based upon the weight of the order, using International Economy Shipping.

When the warehouse attempts to fulfill this order, they find that they must break it into 3 fulfillments, as Box 1 of 3, 2 of 3, and 3 of 3 are not accepted by Netsuite.  (This is fully supported by Fedex international shipping, not supported by Netsuite).