Steering wheel shudder

[Mht3030]

Hi everyone. Hope all is well.
I have a slight issue with my rs6 c7. I unfortunately hit a curb about a month ago, and as a result my steering wheel developed severe vibration while turning at low speeds. It started off only vibrating on sharp turns and developed to vibrating on even small turns.

Took it into a reputable specialist, they said the only issue they can identify is split bushes on the lower control arm and a cracked drop link.

Changed inner and outer lower control arms on both sides, changed drop links on both sides and done a wheel alignment which came out all in the green. All oem parts.

Picked the car up, it's driving 100x better however, I am still getting slight vibration in the steering wheel when I make 90 degree turns at low speed.

The issue does not happen on full lock or very sharp turns. Issue is only present on slight turns, up to about 90 degrees.

Any ideas what could be causing it?

Specialist says it could be quattro grumble as its 4 wheel drive, but he will only know when he feels it, will be taking it back this week but was hoping to get some thoughts until then.