Strange dsg noises

15 months ago I had my 2019 vrs in with the dealer because the dsg gearbox was making noise at low rpm between 2 and 3 and was also making a hissing sound when changing gears. They ended up doing whatever their technical term is for resetting it to relearn. 
 

Fast forward to yesterday after everything having been ok since last year and the odd noises are back. I’ve got what I would describe as a metallic noise between 2 and 3 at low rpm and the hiss on gear change is back. I’m going to get it back with the dealer and see what they’ve got to say, does anyone have a clue what it could be?