Thank you for bringing this to our attention, it does look like because the config setting “Serials - Default Serials To Component Serials If Present” is active it is using the serial number again and updating the date code and lote code to match the ‘Sales Order’. This is to mark that serial with the date of sale.
That is currently what is happening with the Date Code and Lot Code being changed for the same Serial number.
When looking at the PO 4615.1 (the original source PO) this PO is still open and does not have any reciepts made from it. The Source PO 2357.1 was from invoice 2506.1 (/invoice/2367/part_details) here is where the serial 21310022 which is supposed to be from PO 2357.1 is not even on the invoice serials for 2506.1
We will get a case together to test this out and work on a fix for you. We will get back to you as soon as we have an update.