{{Quickfixn}} We received an extra Acknowledgment (39=0 in a 35=8) in response to some New Order Single messages

[Mark Cooke]

We are using FIX 4.0 via QuickFix/N
This happened on 4 New Order Singles, around the same time this morning.
I don't see anything odd, other than getting a 2nd Acknowledgment for 
these 4.

In our application, we'd already updated the state of our trade to be 
Pending, upon processing the 1st acknowledgment for each.
The 2nd ones did not have PossDupFlag or PossResend.
They had new Sequence Numbers.

This did not cause a problem and not long after, we actually received 
Fills and processed those without incident.

I only noticed because we've added a process to monitor our table where 
we record received messages and it alerts if any were received but not 
processed in a "reasonable" amount of time.

I've forwarded the details to our counterpart who sends our messages to 
the brokers and sends their responses back to us, to see if anyone had 
any insight or explanation.

But I thought I'd ask the group if anyone has any ideas for me.

Thanks in advance, Mark