Engine sputter under sport mode high rpm and goes above 4k rpm before having 500 mile

Just picked up my new Z51 today and did some hard accelerations from a rolling start in sport or track mode the motor starts sputtering at high rpm, I also noticed the motor went above 4000 rpm, I was under the impression that the first 500 miles it is limited to 4k rpm during that break in period. Love the power it gets up and scoots.