hey Nick
I saw your post at vmware commnuities, and I responded there as well. I have the same problem and have been working with Cisco TAC, vmware, and EMC on this issue and still don't have an answer.
Did you resolve this issue by upgrading to 2.2(2C)?
Did you have any RDM's attached to your VM's? I do, and that seems to be where most of my problems are coming from.
Any information would be greatly appreciated.
Joe