This started fairly recently. At the beginning of a round of Southsun Survival, all players have 1000 hitpoints. During the first two minutes, there is a grace period where if someone is killed they respawn and are still in the game. During the grace period, after a respawn, the player display does not show up as 1000 hitpoints. Environmental enemies (karkas) do less damage to respawned players as well, normally they one-shot you. Damage from players seems the same before and after respawn.
I will report this in-game the next time that Survival comes up in the rotation.