Removing my Cat and installing a custom slip on exhaust solved my twitchy throttle. Smooth as butter and sounds great now. Trade off is torque seems less and RPM climbs so fast without notice. I haven't changed the map or tested top speed or put on dyno for true objective results. Nevertheless, I still highly recommend.
I'm having exactly the same problem, I've done about 350 miles so far. It's worse when cold but doesn't get a huge lot better when warmed up. I can't get the revs up too high down my lane which is a narrow single track farm lane with loads of blind bends, but it makes no difference if I keep it in 1st or 2nd it lurches and jumps to the end of the lane no matter what I do! Even when out on the open road I cannot find any place where it is totally smooth except for the dual carriageways.
I'm hoping there will be something that can fix or improve this down the line as I love the bike otherwise