Amazon - Mystic haverst

Does it work with lightning spear? grok says yes, but in tool tip there is still just phys leech mentioned in my lightning spear sheet.

I cant see the difference in battle, which makes me feel like its not working cause i have only 700-1K phys (12% leech) and 7K-10K lightning dmg (which means, if it was going of the lightning it should be huge difference).