And when that happens it spits out this into the debug log.

Exception ticking hediff (NanomachinesSon_Heart heart ticksSinceCreation=60000) for pawn Darcey. Removing hediff... Exception: System.InvalidCastException: Specified cast is not valid.
at CF.CommunityHealthUtility.RestorePartRecursiveInt (Verse.Pawn pawn, Verse.BodyPartRecord part, System.Boolean& alreadyWarned) [0x00024] in <42e42d24bf9f4ead83bb97c11c9120ff>:0
at CF.CommunityHealthUtility.RestorePartRecursiveInt (Verse.Pawn pawn, Verse.BodyPartRecord part) [0x00002] in <42e42d24bf9f4ead83bb97c11c9120ff>:0
at CF.CommunityHealthUtility.RestorePartInt (Verse.Pawn pawn, Verse.BodyPartRecord part) [0x0000e] in <42e42d24bf9f4ead83bb97c11c9120ff>:0
at CF.CommunityHealthUtility.TryHealRandomPermanentWoundFor (Verse.Pawn pawn, Verse.HediffWithComps cause, System.Collections.Generic.List`1[T] blacklist, System.Collections.Generic.List`1[T] whitelist, System.Collections.Generic.List`1[T] sideEffects, System.Boolean canHealDestroyed, CF.CommunityHealthUtility+InjuryRegenListMode injuryMode) [0x00075] in <42e42d24bf9f4ead83bb97c11c9120ff>:0
at CF.HediffComp_HealPermanentWoundsConfigurable.TryHealPermanentWound () [0x0003e] in <42e42d24bf9f4ead83bb97c11c9120ff>:0
at CF.HediffComp_HealPermanentWoundsConfigurable.CompPostTick (System.Single& severityAdjustment) [0x00028] in <42e42d24bf9f4ead83bb97c11c9120ff>:0
at Verse.HediffWithComps.PostTick () [0x00024] in <cd7169108ea74757aa50c5b33d275c15>:0
at (wrapper dynamic-method) Verse.Pawn_HealthTracker.Verse.Pawn_HealthTracker.HealthTick_Patch1(Verse.Pawn_HealthTracker)
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) Verse.Log:Verse.Log.Error_Patch1 (string)
(wrapper dynamic-method) Verse.Pawn_HealthTracker:Verse.Pawn_HealthTracker.HealthTick_Patch1 (Verse.Pawn_HealthTracker)
Verse.Pawn:Tick ()
Verse.TickList:Tick ()
(wrapper dynamic-method) Verse.TickManager:Verse.TickManager.DoSingleTick_Patch4 (Verse.TickManager)
Verse.TickManager:TickManagerUpdate ()
Verse.Game:UpdatePlay ()
Verse.Root_Play:Update ()