OOPs, i'd bet that someone made a wrong setup and a whole lot of parts were made incorrectly. Thats the thing about computer controlled machinery, it can do a lot of damage quickly, but to fix it you have to get more raw material which might be hard to get if it is specifically made for the purpose, like lens blanks, for example.
They probably started up the assembly line and found out the hard way. Maybe the prototypes were tweaked but the drawings or machine programming did not get updated. If the glass was ground wrong, thats a expensive error.