Heya, I narrowed the following problem down to Hospital by removing it from the modlist. Then confirmed by loading ONLY Hospital and its dependency along with the core game and official DLC's.

It's causing pawns not to be registered as world pawns. Here's the copy of the two errors it generates when I send a pawn to a caravan with Hospital installed:

1st Error Message:
Error in lord's preAction: System.NullReferenceException: Object reference not set to an instance of an object
[Ref AAF2FC44]
at Hospital.Patches.PatientOutcome_Patches+Notify_MemberExitedMap.Prefix (Verse.Pawn member, System.Boolean freed) [0x00006] in <8b170b95ecb64fa49c86de261c10b7b9>:0
at RimWorld.Faction.Notify_MemberExitedMap (Verse.Pawn member, System.Boolean freed) [0x0001c] in <f0ac5eb9b52e4cc396c70fc9a4ee15e5>:0
- PREFIX Adamas.Hospital: Boolean Hospital.Patches.PatientOutcome_Patches+Notify_MemberExitedMap:Prefix(Pawn member, Boolean freed)
at Verse.Pawn.ExitMap (System.Boolean allowedToJoinOrCreateCaravan, Verse.Rot4 exitDir) [0x0021b] in <f0ac5eb9b52e4cc396c70fc9a4ee15e5>:0
at RimWorld.Planet.CaravanExitMapUtility.ExitMapAndCreateCaravan (System.Collections.Generic.IEnumerable`1[T] pawns, RimWorld.Faction faction, System.Int32 exitFromTile, System.Int32 directionTile, System.Int32 destinationTile, System.Boolean sendMessage) [0x000b2] in <f0ac5eb9b52e4cc396c70fc9a4ee15e5>:0
at RimWorld.Planet.CaravanFormingUtility.FormAndCreateCaravan (System.Collections.Generic.IEnumerable`1[T] pawns, RimWorld.Faction faction, System.Int32 exitFromTile, System.Int32 directionTile, System.Int32 destinationTile) [0x00000] in <f0ac5eb9b52e4cc396c70fc9a4ee15e5>:0
at RimWorld.LordJob_FormAndSendCaravan.SendCaravan () [0x00044] in <f0ac5eb9b52e4cc396c70fc9a4ee15e5>:0
at Verse.AI.Group.TransitionAction_Custom.DoAction (Verse.AI.Group.Transition trans) [0x0001c] in <f0ac5eb9b52e4cc396c70fc9a4ee15e5>:0
at Verse.AI.Group.Transition.Execute (Verse.AI.Group.Lord lord) [0x00028] in <f0ac5eb9b52e4cc396c70fc9a4ee15e5>:0
UnityEngine.StackTraceUtility:ExtractStackTrace ()
Verse.Log:Error (string)
Verse.AI.Group.Transition:Execute (Verse.AI.Group.Lord)
Verse.AI.Group.Transition:CheckSignal (Verse.AI.Group.Lord,Verse.AI.Group.TriggerSignal)
Verse.AI.Group.Lord:CheckTransitionOnSignal (Verse.AI.Group.TriggerSignal)
Verse.AI.Group.Lord:ReceiveMemo (string)
RimWorld.GatherAnimalsAndSlavesForCaravanUtility:CheckArrived (Verse.AI.Group.Lord,System.Collections.Generic.List`1<Verse.Pawn>,Verse.IntVec3,string,System.Predicate`1<Verse.Pawn>,System.Predicate`1<Verse.Pawn>)
RimWorld.LordToil_PrepareCaravan_Leave:LordToilTick ()
Verse.AI.Group.Lord:LordTick ()
Verse.AI.Group.LordManager:LordManagerTick ()
Verse.Map:MapPostTick ()
Verse.TickManager:DoSingleTick ()
Verse.TickManager:TickManagerUpdate ()
Verse.Game:UpdatePlay ()
Verse.Root_Play:Update ()

2nd Error Message:
Caravan member Stevuh is not a world pawn. Removing...
UnityEngine.StackTraceUtility:ExtractStackTrace ()
Verse.Log:Error (string)
RimWorld.Planet.Caravan:CheckAnyNonWorldPawns ()
RimWorld.Planet.Caravan:Tick ()
RimWorld.Planet.WorldObjectsHolder:WorldObjectsHolderTick ()
RimWorld.Planet.World:WorldTick ()
Verse.TickManager:DoSingleTick ()
Verse.TickManager:TickManagerUpdate ()
Verse.Game:UpdatePlay ()
Verse.Root_Play:Update ()


Hope ya find that info useful :) Looking forward to playing with this mod again when that's repaired.