The reinvigorated node reads that if the defender gains regen effect while not being heal blocked, they gain a vigor charge and at 10 charges, they go unblockable. I used warlock against omega red and with 3 infections, he was still gaining vigor charges each time the defender gained a regen effect from aggression regen node. Pics attached
Node description:

8 vigor charges with 3 infections:

9 vigor charges:

Unblockable at 10:

Same thing happened when I used void against gwenpool. She was going periodically unblockable with 2 FOTV effects and the heal block Icon showing clearly.