User blog comment:Xilinoc/Ch. 540 - The Sword Five/@comment-7630025-20130606091757/@comment-7630025-20130609103617

yeah but Isshin also could have acquired that from using his reaitsu to keep the hollow at bay from Misaki. Same as how a hollow can infect shinigami and humans sometimes maybe a quincy's power contaminated his giving him that ability. No other captain nor commander mentioned anything about a final move losing their power.