I got to rank 17 with Lord Shaxx yesterday, but I cannot reset the rank back to 1 as you would with traditional vendors. But hovering over the red icon, it says a rank reset is available. Also, the symbol above Shaxx is indicating he has something for me to claim, but I have already claimed everything he has. This means I can no longer gain engrams from Shaxx no matter how much Onslaught I play. Hoping this a bug that gets fixed ASAP, otherwise the incentive to grind is almost halved since the only other way to get the weapons is to spend the currency at the chest.