Qty Rec Hold Released by System - need to find out how

Hi,

We are using EBS 12.1.3.

I have a situation where an AP Invoice has been matched a PO, which had a Qty Rec hold placed on it. However, about an hour later the hold was released by "System", with a Release Reason of "Passed Matching Condition", and a "WF Status" of "Manually released":

At the time this invoice was created, there were, and still are, 3 Credit Memos on the system matched to the same PO which have more than enough value to cover the value of this invoice. However, none of them have been validated, and all 3 are on hold.