I literally have gotten 10-14 alpha lupais when decrypting exotics with my titan, even the ones for the warlock and hunter. There is nothing random about this. Chest armor is set to Alpha Lupai presently. Exotic boots never drop nor do exotic heavies. When I farmed 3oC(yes, I did), it was the same. Same set of helmets, same set of arms, all chests alpha lupai, no boots, no heavies.