It seems that problems come in a pair. Just got the car back from dealership re: some issues with ABS module but tthats now fixed. but now i've noticed a few things about the exhaust.
- Not as loud as it used to be on start up
- Doesn't pop and crackle as much as it used to at lower revs
- Not as much "grunt" from the exhaust while accelerating
- When active exhaust is turned on and i rev the car i hear a metallic rattle and click from the rear of the car


I'm assuming there's some issue with the active exhaust valves and hence they arent opening properly, affecting the sound of the car and giving the rattle. Booked an appointment for next week with dealership again.

Anyone else had this issue?

 

Can you post which software updates they performed? There was one (O2 calibration?) which affect exhaust noise on some cars. They subsequently released a revised version, which seemed to fix the exhaust noise.

 

Update: it turned out to be a seized active exhaust flap/valve on the left side of the exhaust. it was seized to be closed, they got it loose and lubricated the valve to prevent it seizing again. said if it happens again they will replace the whole exhaust under warranty.

All is back to normal now.