Life Leech not working

I'm a level 10 ranger on 3.21 hardcore and yesterday invested in .4% life leech on the passive skill tree.

My DPS is 53.1 using a bow but even after shooting and killing multiple targets my health does not go up at all.

I don't have anything equipped to life or mana leech or prevent leech.

I think this should be easy to recreate and test.
Let me know if you need more info.

gameplay showing not working https://www.twitch.tv/videos/1899719691

Thx

I don't claim to know the deeper mechanics of leeching (like rounding?) but I'd guess you aren't doing enough damage for .4% to reach any whole amount of life being gained.

Also on the stat screen make sure you are clicking on the ability you want to see the stats of and not default attack. Not relevant for this case though.