Did you make a fresh install or was it an upgrade from a previous RC-x version? This might help solve the issue, or quicker narrow it down.
ah, this is good to have confirmed, then at least it isn't the upgrade being the issue.
btw it might have become a duplicate issue? If following the link in Chris's post up above.
I can second that, I also don't feel any performance/behavior issues at all from it. Well except perhaps shutting down the VM's in question, which can't be done like normal without opening the dom0 terminal and write qvm-shutdown appVM-name. I highly suspect just killing the AppVM might lead to data corruption.