Hi,
It can be normal under certain heavy traffic load scenarios. Every so often, connections get closed due to RNR NAK timeouts. When a connection is closed it will be re-opened when traffic needs to be sent. The chain of events according to the spec would look similar from the below :
Host X initiates a connection by sending a REQ (starts the 3 way handshake).
Host X Receives the RTU message
At this stage according to the IB spec, Host X, is allowed to start transmitting – so it does.
Unfortunately, Host X received a RNR NAK and it had to destroy the connection.
Once the connection was destroyed a RTU message needs to be sent (since the destroy above is asynchronous)
Finally, RTU messages failed because the connection was closed.
I would probably ignore this if I dont see my application / other dropping packets.