Its the archers paradox. Basically your arrows are not the correct spine to clear the riser. Those 500 should be close but you need to play with either length or point weight. The least expensive way to try correcting it is by playing with point weights. a heavier point will make the spine weaker and probably give you the clearance you need. You can also adjust your nock point up a little and experiment that way. I usually paper tune my bows. It will tell you if it's too stiff ir weak, or if you are nock high or low.
Here's a video that explains paradox. It's a pretty neat phenomenon to watch in slow motion.
They say everything happens for a reason. For me that reason is usually because I've made some bad decisions that I need to pay for.
