Getting pyItemId not found error while  ProCom agent is trying to process a queue item.

Here is the scenario:

On finishing of the assignment, 2 queues are created.

1. Q1 for sending mail processed by Custom agent- pyItemId is like SYSTEM-QUEUE-DEFAULTENTRY XXXX
2. Q2 for SLA processed by Pega ProCOm agent- pyItemId is like SYSTEM-QUEUE-SERVICELEVEL YYYY

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Q1 is always executed before Q2

Q1 is being processed successfully.

While Q2 is being processed, ProCom agent is trying to open the instance of pyItemId created for Q1. As Q1 is already been processed(it will be deleted from system after completion), we are getting exception like : "Unable to open an instance using the given inputs: pxObjClass = "System-Queue-DefaultEntry", pyItemId = "SYSTEM-QUEUE-DEFAULTENTRY XXXX"

Ideally while Q2 is being processed, ProCom agent should try to open the instance Q2 (i.e  SYSTEM-QUEUE-SERVICELEVEL YYYY) not Q1.

Any one has faced this issue? any suggestion for this pls?