There was a consensus that the '+1 Mana From Kills' crafting effect from mana berries was overpowered. It was decided (during a dev stream) that it should be nerfed.

So in beta 5.4 it has been changed, but to call it a nerf, not really.

Instead of replacing the '+1 Mana From Kills' crafting effect with another, we now get it and a '+12 Spell Resist' on top of it. Resulting in that the mana berries are now super overpowered. Can we get a blue bag to carry them in with a big red S on the cloth? 

The ultimate spell slinger killer combo.

"Muhaha, your spells can't hurt me, and after i kill you i gonna take your mana. Muhaha"