I have encounter a problem. This is coming after Approval of the Purchase order. The Draft document of Purchase order is been updated by the second person in charge for approval. When the originator received the message that his request has been approved, and open the draft PO and click update the error shows up.
FYI: There are 10 days gap before the second approval noticed that there is a pending request. Probably the Document number has been stock up or corrupted (just my guest).
There is another one i noticed. same series number has been approved, but i cannot cancel since it is waiting for approval.