Maybe you should e-mail Scott M. Johnson and/or the Windows Server/Storage team directly (like I did) and ask them if it is just a "best practice" to put turn on Redirected mode or if it is in fact a requirement.
Also, another though that I had which could have been the cause of my and mes@faber's problem - when you shrink a LUN, let's say 20GB, does that 20GB now get added to the latest snapshot, and if you don't have enough space allocated to SnapShots with no snap-auto-delete turned on, wouldn't that overflow into your lun space causing alignment corruption?
What I noticed when I shrunk my CSV LUN was that the Failover Cluster Manager didn't see my new CSV disk in size, but it still saw it as the old size. Even in Disk Management I couldn't get the updated size (smaller). SnapDrive successfully shrunk the LUN, but Windows was still seeing it as bigger (original size).
I did open a case and could send you and ONTAPWINDC if you want - ask me privately and I can give you the info you need (or more if interested).