Rares with Endurance charges can become immune to damage

Only at Act 3 and twice I've encountered rares with the "gain Endurance Charges when hit" mod and both times when they get to their max charges (~6) they become immune to phys and elemental damage. Only way to counter them i've found outside of maybe using chaos damage is to wait out the endurance charges and take it down with big hits before the charges build up again. Ignore phys reduction might also work but i haven't tested it just yet.

I've come across regularly on console. Playing a phys bleed dot build and consistency find unkillable rares with the same mod in delve and maps.