On my Diamond Victory I have experienced the same problem. I use Blazers with a right helical. I resolved my problem by turning the nock just a bit. So rather than the cock vane being straight up at 12 o'clock it is at about a 1 o'clock position, well not quite that far, just enough for the vane to clear the cable. I use a Cobra diamondback dropaway and the factory cable slide. Since making this adjustment I no longer have contact.