Time Control issue

Exception ticking Hano (at (148, 0, 29)): System.NullReferenceException: Object reference not set to an instance of an object
  at Verse.ImmunityRecord.ImmunityChangePerTick (Verse.Pawn pawn, System.Boolean sick, Verse.Hediff diseaseInstance) [0x00013] in <7b345446a85d4ed599f9c604ae61854b>:0
  at Verse.ImmunityRecord.ImmunityTick (Verse.Pawn pawn, System.Boolean sick, Verse.Hediff diseaseInstance) [0x00000] in <7b345446a85d4ed599f9c604ae61854b>:0
  at Verse.ImmunityHandler.ImmunityHandlerTick () [0x00065] in <7b345446a85d4ed599f9c604ae61854b>:0
  at (wrapper dynamic-method) Verse.Pawn_HealthTracker.Verse.Pawn_HealthTracker.HealthTick_Patch2(Verse.Pawn_HealthTracker)
  at (wrapper dynamic-method) Verse.Pawn.Verse.Pawn.Tick_Patch3(Verse.Pawn)
  at DTimeControl.TCTickList.TickThing (Verse.Thing thing) [0x00032] in <60d5ee13bd6b49e0aad5eb8b68d8d984>:0
Verse.Log:Error(String, Boolean)
DTimeControl.TCTickList:TickThing(Thing)
DTimeControl.TCTickList:DoTick(Double, Boolean)
DTimeControl.TimeControlBase:TickManagerTick(TickManager, Boolean)
DTimeControl.Core_Patches.Patch_DoSingleTick_Prefix:Prefix(TickManager)
Verse.TickManager:Verse.TickManager.DoSingleTick_Patch4(TickManager)
Verse.TickManager:TickManagerUpdate()
Verse.Game:Verse.Game.UpdatePlay_Patch2(Game)
Verse.Root_Play:Verse.Root_Play.Update_Patch1(Root_Play)