2017 S4 B9 - Shaking / Rocking on idle?

Hi guys, so just serviced my s4 b9 and changed up from 0w20 to 5w30 with ceratec. Cars on 85000 miles (135k km). I’ll be honest, no faults with the car at all, drives spot on. Only one worry I have is at idle, the car will rock almost left to right and have just generally a rock in the cabin. It’s not like a rough idle. It’s just the cabin rocks? I don’t know how else to explain it! Is this normal for b9 s4’s? Or should I go get my engine inspected? (Everything else is running fine, just this idle thing worry’s me!)