It indicates a leak of some description. Just because you fitted a Rev D does not mean that the solenoid driving the valve hasn't failed. If you have an intake, you can audibly hear whether the N249 (Diverter valve) is doing its job or not.
If its not that, get checking for leaks, including the PCV etc. making sure everything is airtight
Failing/faulty throttlebody is another option - try running the TB adaption on VCDS