Thank you, but I'm sure that's not what's happening.
I spent almost two hours staring at the combat log. It's not just misses and grazes, the heal fires up unreliably even when I hit or crit (actually it is, but only the white flame animation, no healing).
When dual wielding (i think) I get at least one heal, sometimes from the main hand attack, sometimes from the offhand. Only time I sometimes don't get a heal is when the main hand kills the target.
I was sure that it was just nerfed because dual-wielding was too OP. Seemed reasonable. I wanted to use a bow as the second weapon set anyway so I started a new herald. This time with twohanded weapons. First I didn't pay attention, thinking it was just grazing hits when I didn't get the healing, but at the digsite I started checking the log. Pike, bow, pollaxe, all unreliable, even when hitting or critting.
I'm on the xbox pass version of the game. Don't know if that's relevant.