My 2018
290 with GPF pops and bangs big style on over-run when downshifting in sport mode. I also get some some juicy farts when pushing it.
My car has 9k on it now so I think the exhaust needs a bit bedding in.
When I set off in M1 then change to M2 at about 3.5k revs I get a deeply satisfying low fart/grumble.
I've never noticed it stopping after a while. My car seems to do it all day if you're in Sport/
Cupra mode. I tend not to use
Cupra mode due to the intrusive Soundaktor. I'll eventually physically disconnect it!