I always release the halyard tension after furling the jib, and then tension it again before un-furling. I am not sure a tensioned halyard explains the wear you see. I woukd wonder whether the halyard has the right angle to the exit block, if the angle is too small, I would think the halyard would be trying to wrap, perhaps creating wear at the exit box even if the tension is enough to prevent an actual wrap. For example, my recent furler setups have all had a halyard retainer ( basically a strap) below the exit box, to ensure a wide angle at full hoist.