Hi,
At DSO, you may have two requests.
Based on request loaded date you can track the data from DSO to (PSA and source )lower data flow.
at BW side you can't find any thing about it,.
You need to find at source side only. you better consult source team and find all chanegd history for your doc number.
Check at Source side RSA3 for your document number and see whole reocrd combination data.
You may find the changes. need to delete and fill setup tables for LO data source.
Thanks