Order number printed on pcb

Hi, i've got a question:

I ordered some PCB's @ your company, but with this proto type; every time the order number is printed on the silkscreen of the pcb; can you tell me why this is?

It's only with this design; if i look at the gerber files i can't find any reason for this and i never had it before.

(Order #: Y39-2204361A), Y38-2204361A, Order #: Y32-2204361A.

(In this case it doesn't matter that the number is in the print; but i prefer not to.)

Like to here from you.

Regards, Reinald Nijboer