i would say your cut is too long, and you are shifting lazily. leave the 4000 rpm limit in place. make sure you pull up on the shifter firm, fast, and positively. you have to override the movement of the pressure sensor, to get the fuel cut to get it into gear.
if you cant get your foot high enoguh fast enough, lower your shifter lever.
working with my wife on this EXACT problem right now on her track bike, except, she is missing 5 and 6th gears. ski
May we all, get to have a chance to ride the fast one, walk away wiser when we crash one, keep hopin that the best one is the last one.