Claw mastery instant leech - bugged/zero effect

As title says, instant leech notable of claw mastery doesn't work. Might also be the case for life/mana leech, but this is much harder to confirm due to lgoh/mgoh effects

Noticed/confirmed it the following way:
My build uses both leech mastery and claw mastery with instant leech. Thinking 15% instaleech was a bit overkill for what I was doing at the time, I unspecced the leech mastery. I noticed my ES would be bottomed out even while fighting large packs of mobs, it took me a long time and many deaths to finally figure out what was going on. I was only getting the slow and steady trickle of normal ES leech, as soon as I took the 5% instant leech mastery my ES would shoot back up instantly when fighting packs.

Would like to bump this post and can follow up with some more details - the 5% mastery from Leech Mastery works as intended, IF you convert generic Attack Damage Leeched as Life to Energy Shield Leech via ghost reaver. If i only have the CLAW mastery instant leech, and no ghost reaver, but i DO have generic Energy Shield leech such as from the Storm Drinker cluster notable, instant does not apply. Currently this bug is costing me several levels of passive points as I have to take generic leech AND convert to ghost reaver, effectively turning off my recharge which would otherwise not be required if the Claw Mastery worked on Generic Energy Shield Leech.