I can tell you that is would not have happened. There is no way a colored paper print would have been produced on white paper and not have been spotted by quality control not to say someone other in the print team. I can assure you not even set up would have been done on white paper. I never ever saw a mistake of this magnitude being made. Sorry but I agree those stamps have been exposed to chemicals. I do not even see sun light doing this and yes they would have been made in quantity. Yes you would have mint stamps If this was done at the BEP or one of the other vendors.