Cannot Close AR Due To Unprocessed Third Party Merge Events

 Hi Experts,

I am unable to close AR period and the Subledger Period Close Exception shows rows with Event_Type = PARTIAL MERGE and Status = Unprocessed, but does not list the item(s) these events are associated with, so unable to identify to run diagnostics for further investigation.

I found this note: APP-AR-294571 Cannot Close AR Due To Unprocessed Third Party Merge Events [ID 1328956.1] which tells me to run concurrent request 'Create Accounting For Third Party Merge' but before I do that, I would like to understand why am I seeing this row now for the first time? 

Also, how can I find what parties are merged? Let me know what you think.