I suffered this on my Gen1... when brake hard and downshift quickly, the clutch lever make some chatter (kicks)
I follow all recomendations that I found and only one works, you can try it all, or go directly to the last
First I dismounted the clutch and soap the rings and plates in new oil all the night. (no gain)
Changed the clutch springs by others from the race kit. (light gain)
I changed the angle where the gear bar pulls the gear selector. (more gain)
Swapped the whole clutch, basket and plates, by another "used". (the chatter dissapear)
After a Gen1 , and Gen3, finally my Gen5 ride hard with some gifts.