Hi Oai,
As I investigated the sales order # 140565213. There are created the DO 4904457092 and 4904476928 for 2 PC in each DO. It should be separated the DO by manually.
The attachment file is the history of documents list, which system generated about Goods Receive(101), Goods Issue(601), Goods Transfer(343,344), Goods Return(653,654). You can see the yellow lines and another one line. It means that this material code is available for that sales order.