Exception in JobDriver tick for pawn Mech_Scyther23346 driver=JobDriver_AttackMelee (toilIndex=2) driver.job=(AttackMelee (Job_7997) A=Thing_AIRobot_Hauler31239) lastJobGiver=RimWorld.JobGiver_AIFightEnemies
System.NullReferenceException: Object reference not set to an instance of an object
at Verse.Pawn_HealthTracker.NotifyPlayerOfKilled (System.Nullable`1<Verse.DamageInfo>,Verse.Hediff,RimWorld.Planet.Caravan) <0x0033c>
at (wrapper dynamic-method) Verse.Pawn.Kill_Patch5 (object,System.Nullable`1<Verse.DamageInfo>,Verse.Hediff) <0x01b9a>
at Verse.Pawn_HealthTracker.CheckForStateChange (System.Nullable`1<Verse.DamageInfo>,Verse.Hediff) <0x0011b>
at Verse.Pawn_HealthTracker.AddHediff (Verse.Hediff,Verse.BodyPartRecord,System.Nullable`1<Verse.DamageInfo>,Verse.DamageWorker/DamageResult) <0x000c8>
at Verse.HediffSet.AddDirect (Verse.Hediff,System.Nullable`1<Verse.DamageInfo>,Verse.DamageWorker/DamageResult) <0x004ae>
at Verse.Pawn_HealthTracker.AddHediff (Verse.Hediff,Verse.BodyPartRecord,System.Nullable`1<Verse.DamageInfo>,Verse.DamageWorker/DamageResult) <0x00087>
at Verse.DamageWorker_AddInjury.FinalizeAndAddInjury (Verse.Pawn,Verse.Hediff_Injury,Verse.DamageInfo,Verse.DamageWorker/DamageResult) <0x0013c>
at Verse.DamageWorker_AddInjury.FinalizeAndAddInjury (Verse.Pawn,single,Verse.DamageInfo,Verse.DamageWorker/DamageResult) <0x00305>
at Verse.DamageWorker_Stab.ApplySpecialEffectsToPart (Verse.Pawn,single,Verse.DamageInfo,Verse.DamageWorker/DamageResult) <0x002d7>
at Verse.DamageWorker_AddInjury.ApplyDamageToPart (Verse.DamageInfo,Verse.Pawn,Verse.DamageWorker/DamageResult) <0x004a9>
at Verse.DamageWorker_AddInjury.ApplySmallPawnDamagePropagation (Verse.DamageInfo,Verse.Pawn,Verse.DamageWorker/DamageResult) <0x002ca>
at Verse.DamageWorker_AddInjury.ApplyToPawn (Verse.DamageInfo,Verse.Pawn) <0x003b0>
at Verse.DamageWorker_AddInjury.Apply (Verse.DamageInfo,Verse.Thing) <0x000be>
at Verse.Thing.TakeDamage (Verse.DamageInfo) <0x002dd>
at RimWorld.Verb_MeleeAttackDamage.ApplyMeleeDamageToTarget (Verse.LocalTargetInfo) <0x0016c>
at RimWorld.Verb_MeleeAttack.TryCastShot () <0x007c3>
at Verse.Verb.TryCastNextBurstShot () <0x0006c>
at Verse.Verb.WarmupComplete () <0x0003b>
at Verse.Verb.TryStartCastOn (Verse.LocalTargetInfo,bool,bool) <0x004cf>
at RimWorld.Pawn_MeleeVerbs.TryMeleeAttack (Verse.Thing,Verse.Verb,bool) <0x002bd>
at Verse.AI.JobDriver_AttackMelee/<MakeNewToils>c__Iterator0.<>m__1 () <0x00085>
at Verse.AI.Toils_Combat/<FollowAndMeleeAttack>c__AnonStorey3.<>m__0 () <0x00340>
at Verse.AI.JobDriver.DriverTick () <0x004a8>

Verse.Log:Error(String, Boolean)
Verse.AI.JobUtility:TryStartErrorRecoverJob(Pawn, String, Exception, JobDriver)
Verse.AI.JobDriver:DriverTick()
Verse.AI.Pawn_JobTracker:JobTrackerTick()
Verse.Pawn:Tick()
Verse.TickList:Tick()
Verse.TickManager:DoSingleTick()
Verse.TickManager:TickManagerUpdate()
Verse.Game:UpdatePlay()
Verse.Root_Play:Update()