I think it is as blocking as how he triggers his regen and that cost a him power so on heal block nodes your best bet is to not block and rely on intercepting and evading
It's the same idea that regen still proc's on heal block or spidey's taunt still tries to proc on the opponent and he loses a poise on debuff immune. Things still go through their typical mechanic, you just don't see the final effect.
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I just think it's a bit weird that he loses power without gaining the regen