Hi,
I am not sure why you are using 351 for GR for an STO PO.Is this STO is inter plant under a company code or with differant company codes ?
also please check the same batch is existing in both the plants and what are the details for the date of manufacture .You are telling that the batch date of manufacture is 29.12.2012 and the total shelf life is 60 , the bathc would have been expired . please check . if you enter the same batch in MIGO screen during 351 to issue to stock in transit , asunming that the suppy plant is issuing the goods to the receiving plant , hoping that the system needs a date of prod as this is a fresh send of supply and since you are using the old batch number could be a descrepency ?
Please check in the above point of view also.
Regards,