Serial controlled item on a split line

Have an item that has become serial controlled. The generation method is predefined. During our conversion from non-serial control to serial control it wasn't noticed that one line in shipping was split. So now when the shipping folks are trying to pack with the serial number they are stuck because it is .5 & .5 for the line item. Obviously a serial number can only be used for a "whole" unit.

A few questions...any thoughts on getting around this? Second question is how do other people deal with splitting lines on serialized items?

Thanks in advance