I have created 2 Delivery document and was able to use the same serial number.
For the first delivery document second line item has only 1 quantity delivery1.jpg but see screenshot for serial number allocation, system was able to allocate 2 serial number for that item which seems to be wrong since the quantity of the item is only 1. serial-number-allocation.jpg. For the next delivery document del2.jpg, system was also able to use the same serial number with the previous attached delivery document.
May I ask what could be the cause of allowing same serial number for the same items but with different delivery reference? Would highly appreciate your response.