Try recording your RR pairs again with the following sidecar file:
msg.expiry=-1
msg.messageSequenceNumber=1
msg.originalLength=-1
msg.persistence=2
msg.priority=-1
msg.putApplicationType=0
There is a bug, fixed in 9.0, where some of the default MQ header properties put into your VSI by the RR pair process are incorrect. The above properties, put into a sidecar file will, correct it. You could also make the changes directly in every response's meta-data, or simply remove those properties from your responses' meta-data.
There is also a patch available if you want to contact support, the internal case number is RTC-235451. You will still need to re-generate your service images after applying the patch, so I would just try the sidecar file first.