The quicksilver for me has been awful and super ....... dangerous. I want to say 6 out of 10 shifts from 3rd to 4th or 4th to 5th it acts like it goes into neutral and then bucks super hard. I hate it. I never have this problem with my 2019 R1.
Make sure you are on the gas when you shift. If you the throttle is even rolling off slightly then it will lurch. Also, after making the shift, ensure you don't have any pressure on the lever or it won't complete the shift. In other words tap up (or down) but don't keep any pressure on the shifter after the initial engagement.
Not saying the QS is great (it's not) but it's also extremely sensitive to the above.