Lemme guess you had the Twilight shield witch power on your toon?
That damn thing has been broken since the start of the season. They’ve tried fixing it before and failed and now they’ve disabled it again.
This has been a horrible season for HC. Monsters can wander into towns and kill you. You can be killed by other players in non-PvP zones. And Blizzard just twiddles their thumbs and cranks out more cosmetics for the shop.