Do you have another ILF riser that you could throw the limbs onto to see if it is a limb noise or a riser noise? I recently got a set of those too, I put them on an off-brand riser and had to adjust the dovetail all the way to one side to get the string to hit the grooves, I was thinking maybe as you started to draw, the strings were popping over into the string grooves before you got the draw back far enough to completely clear the grooves and obviously that's only if your strings aren't in the grooves already, just speculating from afar.