It certainly looks like the installation was different between QA & PR.

The information you gave is still suggesting that the SQL Server instance was not installed in the Virtual Server named 'PR1'. Instead it has been installed into the cluster group CL2.

If you would like to confirm this, please check Cluster Admin as mentioned in my previous 2 posts...

Where to from here?

It might be possible to move a Clustered SQL Server instance into a different cluster group (e.g. Move all the SQL resources from CL2 into PR1), however unless you can find a solid reference on how this can be done I highly recommend you do not follow this path.

Even if you do manage to move the SQL resources into PR1, you will always have a difference between QA & PR. This difference may not be visible straight away, but somewhere in the registry there could be a difference, and when it comes time to install a hotfix, service pack, or upgrade to SQL 2008, that’s when the problems will arise...

If it were my cluster, I would rebuild it (including OS). If that was not possible then uninstall / reinstall the SQL instance only.