Life leech is completely nonfunctional

Without Herald of Ice, or Hatred running, and with Mortem Morsu in my primary hand, my base physical damage is 91-378. None of my strikes should be hitting without giving me back health. I just sold back two dex nodes that were on the way to something else, and bought the Blood Drinker node to raise my life leech a little more.

I have 975 hp. The stats indicate I have life leech from physical attacks of 2.8%.

At 1500 or so physical dps and 2.8% leech, I should be getting @42 health back per second on average, and I'm getting nothing even close to that.

I am seeing slight upticks happening. I thought that they were caused by the offhand weapon stats since they were so tiny that they weren't occurring every hit.

If I am receiving zero benefit from the offhand +health (I thought it was a global modifier like stats) then I must be getting the health from life leech. However, I should be able to completely fill my health bar in 23 seconds if I am being attacked by something like a zombie that either doesn't hit me, or that hits me and only does damage to my shield, not my health. A yellow zombie several levels lower then me lasts 2-3. Long enough that I should see a substantial uptick in health, 42 hp per second on a 975 hp health monitor is noticeable.

What actually happens is that my health improves a pixel or two over the course of 2 or 3 seconds, instead of 10%+ as it should.

Are those base numbers default attack or your actual skill tooltip? At 91-378 damage per hit you should average 6 life every time you hit. You can't look at pixels. You have to look at the numbers. How much numerically does the number change each hit?

I don't think monsters have much armour, but that would mitigate the damage as would the attacks missing or getting blocked.