[1.1.2598] Pigs are immortal

[CanMan]

Currently having a bug where I can't slaughter some of my pigs. The pawns have cut the pigs necks (sometimes repeatedly) and the pigs have "bled out" but stay at 0 hours until death as they slowly heal. I've disabled all mods so I think it's a vanilla issue. Using dev mode to kill them doesn't work, but destroying them does disappear them. The error log mentioned relationship tracker, so I followed along that trail and removed pig 91's relations from it's parents, but it still wouldn't die. I noticed it had 4 children, so I went through them and removed pig 91 as their parent, and finally it was able to die. Seems to be a family tree issue. Dogs seem to be immune to Dev tool: kill as well.

I re-enabled my mods but here's the log when I try to use dev mode to kill a pig:

https://gist.github.com/ff8b6e1dd6b30c321df7fa85df0e65e1

Not a programmer but this seems to be the relevant part:

Exception ticking Pig2087234 (at (115, 0, 168)): System.NullReferenceException: Object reference not set to an instance of an object
  at RimWorld.Pawn_RelationsTracker.Notify_PawnKilled (System.Nullable`1[T] dinfo, Verse.Map mapBeforeDeath) [0x0001d] in <c8e8d421567e4ee5864626a429a27a37>:0
  at Verse.Pawn.Kill (System.Nullable`1[T] dinfo, Verse.Hediff exactCulprit) [0x002a2] in <c8e8d421567e4ee5864626a429a27a37>:0
  at Verse.Pawn_HealthTracker.CheckForStateChange (System.Nullable`1[T] dinfo, Verse.Hediff hediff) [0x00020] in <c8e8d421567e4ee5864626a429a27a37>:0
  at Verse.Pawn_HealthTracker.Notify_HediffChanged (Verse.Hediff hediff) [0x0000b] in <c8e8d421567e4ee5864626a429a27a37>:0
  at Verse.Hediff_Injury.Heal (System.Single amount) [0x0003e] in <c8e8d421567e4ee5864626a429a27a37>:0
  at Verse.Pawn_HealthTracker.HealthTick () [0x0027d] in <c8e8d421567e4ee5864626a429a27a37>:0
  at Verse.Pawn.Tick () [0x000bb] in <c8e8d421567e4ee5864626a429a27a37>:0
  at Verse.TickList.Tick () [0x0015c] in <c8e8d421567e4ee5864626a429a27a37>:0
(Filename: C:\buildslave\unity\build\Runtime/Export/Debug/Debug.bindings.h Line: 35)

Maybe immortality runs in the family?

[Cepstrum]

Sorry to tell you this, but this kind of exception is caused by mods and messes up a saved game even after you remove the mod that caused it. I had it recently myself, in my case I triggered it by removing EPOE from my game. Though I'd appreciate if this error was handled and let the NPC die, mods or not.

But I don't have your save or mods so I could be wrong. Just try starting a new game, spawn a pig, and try slaughtering again. Try it with and without mods too.