This is an old thread to resurrect, but I have these exact symptoms. Seems to happen most frequently when I'm exiting roundabouts, but I think that's just because I'm in the right range. Same in drive or tiptronic. I'd thought it was a wheel / balancing issue tbh.
Mackies had quoted £275.00 + VAT for a full service / flush just before the lockdown started. Any ideas what repairing / replacing the TC is likely to add to that figure? Looks like I might have more re-budgeting to do.