I just thought I'd post a new thread to hopefully combine all the other 'detune bug' threads into one. Maybe we can look for possible causes, rather than waiting for Access support to forward the many problems to the engineers and find no solutions after months.
PROBLEM: When the Virus TI is used in USB mode, there is the tendency for the pitch to oscillate up and down slowly. (Aparrently this problem does not occur with Macs.)
MY THEORY: I believe the PLL used to keep the TI's internal clock in sync with the USB port may be buggy or poorly designed. It's just a theory, but after researching a little into electronics, I believe it could be one possible area for the engineers to look at.
The reason I have come to this conclusion is that nothing else could possibly be causing a slow oscillation of the pitch. When the TI is used on its own, the pitch is 100% stable - only when the TI is connected to and has to maintain sync with a host does it exhibit this problem.
[ One workaround in Cubase is to keep changing the ASIO buffer size from any value to any other until you hear the pitch is holding steady. Then you can continue working on your project until it decides to start oscillating the pitch again. ]
EDIT: Video of the problem: http://www.youtube.com/watch?v=j6KCI-u6A_w