One map affix refers to leech being nerfed, but leech is no longer in the game, leading to a very confusing player experience.
Leach was replaced by HP on hit and MP on hit so they are classed as ‘leach’, and so the leach nerf applies to them
It also applies to Health Orbs, I think? Either way, I know now what leech was changed to, but that doesn’t make it any less confusing to a new player. NOWHERE in the game is that explained, and the term Leech isn’t even in the codex anymore.
To be honest a lot of the game isnt really explained, jist play around with it and it will start to unravel a little to you 
Best way to look at the game is with a fresh memory for each patch, just completely forget about what you remember from before and start to relearn everything in the new update they change a lot but only some of it is shared, they do their best to share patch notes though but some of the little things are forgotten sometimes 
Thanks for the report. Noted.
Actually, the health/mana gained from orbs and potions is labeled as Potion Nerf.