So we just had this issue.

A cad file with multiple configurations created by a design table was added to the vault and checked in all the different configurations had a separate part number (serial)  The next day the user added more configurations to the design table. These configurations did not get a part number.

I looked at the design table and it had a column for part numbers, and the new configurations were blank. So far it looks like the only way for this not to happen is to make sure that the design table does not import the part numbers.   

Is there another way to prevent this from happening?

Thanks!