My 2016 A6 Black Edition saloon (2.0 Diesel) is 9 months old with 8k miles and I'm experiencing a problem with some slight play / movement in the drivers seat. Has anyone else experienced anything similar?

I've got the S-Line variant seats in leather with the alcantera inserts. The seats are heated and have the memory option. The problem is that there is a very minor (left to right and vice versa) movement in the seat when going round corners even at low speed. I had the car into my local dealership and after 5 days / 2 visits they decided to replace the seat frame (under warranty). However it was only a short time before the issue returned and it is happening again now, same as before. The movement is only very slight but all the same really annoying and it feels like the seat is moving on the rails but it is only sideways

It's booked to go back in again to Audi but I'd appreciate any advice