Castle Creations Baja Conversion kit 750kv vs 780kv

Just have a question, i have the rev 2 and im noticing especially with 8s thats it a bit notchy(not sure about the word).Like when i give it some throttle it hesitate for an split second for so to jump forward.
This isn't something that happens every time i give it throttle but frequently

using 2 4s 5000 45c nanotech, the max ripple is 6% and futaba 3pm radio

i have runned it 3 times, one time with 6s(9% ripple) and 2 times with 8s

Hope for an answer

thanks
Fredrik

edit, im on stock firmware