I have a VW 2015 2L Tiguan TDI BMT 4MOTN with a DSG gearbox.
Yes you've guessed it, in June the software was changed (23R7) under the Nox recall and resulted in a significant rattle when under power at ~1500rpm.
Back to my main dealer, VW Lancaster (Ayesbury), who recommended I took the car out on a test run with a technician. He confirmed the fault and the Service Adviser booked my car in and provided me with courtesy car free of charge.
Contacted by the dealer the next day and told 'the computer is showing no faults' but they would contact VW HQ in Milton Keynes for advice.
The following day I was telephoned and told the car was ready for collection which I did and the fault was significantly better.
Today, I took it for a longer trip and could just detect the rattle but once it warmed up, it was back to it's old self; I can live with that.
The original upgrade was coded 23R7 but the dealer said the software they had most recently used was a new version.
Make of this what you will but in I think main dealer followed a sensible procedure and now I have back a car which is a joy to drive.
Good luck if you have one!