I ran you numbers in my arrow software and your spine is fine. The problem may be your not heavy enough. Your axis looks like its weighing in around 400 grains which puts your speed around 300-305. Form my experience, anytime you try to fly fixed blades above 290, things can get weird. I would either drop your draw weight down if you want to keep shooting that arrow or move to something heavier. Getting in the 430g ballpark would get you in the 280s and will probably help your broadhead flight. You could also try shooting 125 heads or adding 50g inserts to the front.