I have 141% lightning resistance in Hideout, because my gloves, belt, boots and amulet doesn't have resistances (165% is required for Elemental Weakness Mod Map), but since we can use Vessel of Vinktar non stop I'm still over capped (216% lightning resistance). So it doesn't represent any problem.
Maybe u have lightning resistance but maybe i dont have enough lightning resistance and i am paying for that helm so look what i have not what u have.