So I've struggled with this issue in my 2015 Evora S for the past 3 years.
The IPS gearbox works great at high speed and high RPM, but when it comes to automatically downshifting when coming to a standstill, 3-2 and 2-1 gear changes make a loud audible clunk that can be felt through the seats.
On a related note, once or twice a day, the IPS misreads my intentions and violently down shifts and the whole car shakes (it only happens with the 3to2 gear change) when all I wanted was to continue coasting on 3rd gear.
Dealer claims this is normal and can do nothing about it. Note: when the TCU was reset and transmission oil changed, the gear changes became a lot smoother for a few days and then the same issues resurfaced.
Any ideas? I'm at my wits end and will probably have to sell the car if this can't be sorted.