Warlords bloodlust (game)

Hi, not sure if im incorrect here, warlords blood lust description is damage dealt to enemy champions (on critical strike) heal you for 15% and grant attack speed. I have noticed that the passive granted by this mastery no longer happens at all. could someone please check it out?? or explain why its not happening. Ive played a few champs, a lot being yasuo, during crits i have no been healed. ive watched adc's not get healed by the passive either.