The void charm teleports the player to their bed when they would be put under 5 hearts of health (also canceling the instance of damage), but because it uses mana and artifice's TeleportHelper.teleportEntity method, which does a delayed teleport 2 seconds later, the player can die from further void damage during that delay. Maybe in the past the method used instantly teleported the player?

Thx, fixed it :) 3.1.11