Seeing this (not-game affecting) error in the log when new guests/caravans are spawned. My guess is, the mod settings stored a def that is no longer loaded (old mod that has been disabled). Might just need a quick if exists check:

Could not load reference to Verse.ThingDef named Apparel_Vest
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.Log.Error_Patch4 (string)
Verse.ScribeExtractor:DefFromNode<Verse.ThingDef> (System.Xml.XmlNode)
Verse.ScribeExtractor:DefFromNodeUnsafe<Verse.ThingDef> (System.Xml.XmlNode)
Verse.Scribe_Collections:Look<Verse.ThingDef> (System.Collections.Generic.List`1<Verse.ThingDef>&,bool,string,Verse.LookMode,object[])
Verse.Scribe_Collections:Look<Verse.ThingDef> (System.Collections.Generic.HashSet`1<Verse.ThingDef>&,bool,string,Verse.LookMode)
Verse.Scribe_Collections:Look<Verse.ThingDef> (System.Collections.Generic.HashSet`1<Verse.ThingDef>&,string,Verse.LookMode)
Verse.ThingFilter:ExposeData ()
Verse.ScribeExtractor:SaveableFromNode<Verse.ThingFilter> (System.Xml.XmlNode,object[])
Verse.Scribe_Deep:Look<Verse.ThingFilter> (Verse.ThingFilter&,bool,string,object[])
Verse.Scribe_Deep:Look<Verse.ThingFilter> (Verse.ThingFilter&,string,object[])
DressForTheWeather.DressForTheWeatherSettings:ExposeData ()
Verse.ScribeExtractor:SaveableFromNode<DressForTheWeather.DressForTheWeatherSettings> (System.Xml.XmlNode,object[])
Verse.Scribe_Deep:Look<DressForTheWeather.DressForTheWeatherSettings> (DressForTheWeather.DressForTheWeatherSettings&,bool,string,object[])
Verse.Scribe_Deep:Look<DressForTheWeather.DressForTheWeatherSettings> (DressForTheWeather.DressForTheWeatherSettings&,string,object[])
Verse.LoadedModManager:ReadModSettings<DressForTheWeather.DressForTheWeatherSettings> (string,string)
Verse.Mod:GetSettings<DressForTheWeather.DressForTheWeatherSettings> ()
DressForTheWeather.IncidentWorker_PawnsArrivePatch:get_Settings ()
DressForTheWeather.IncidentWorker_PawnsArrivePatch/<>c:<InitializeApparelPairs>b__5_0 (Verse.ThingDef)
RimWorld.ThingStuffPair:AllWith (System.Predicate`1<Verse.ThingDef>)
DressForTheWeather.IncidentWorker_PawnsArrivePatch:InitializeApparelPairs ()
DressForTheWeather.IncidentWorker_PawnsArrivePatch:Postfix (System.Collections.Generic.List`1<Verse.Pawn>&,RimWorld.IncidentParms)
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:RimWorld.IncidentWorker_NeutralGroup.SpawnPawns_Patch2 (RimWorld.IncidentWorker_NeutralGroup,RimWorld.IncidentParms)
GiddyUpCaravan.Harmony.Patch_IncidentWorkers:MountAnimals (RimWorld.IncidentWorker_TraderCaravanArrival,RimWorld.IncidentParms)
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:RimWorld.IncidentWorker_TravelerGroup.TryExecuteWorker_Patch0 (RimWorld.IncidentWorker_TravelerGroup,RimWorld.IncidentParms)
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:RimWorld.IncidentWorker.TryExecute_Patch1 (RimWorld.IncidentWorker,RimWorld.IncidentParms)
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:RimWorld.Storyteller.TryFire_Patch1 (RimWorld.Storyteller,RimWorld.FiringIncident,bool)
RimWorld.Storyteller:StorytellerTick ()
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.TickManager.DoSingleTick_Patch6 (Verse.TickManager)
Verse.TickManager:TickManagerUpdate ()
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.Game.UpdatePlay_Patch2 (Verse.Game)
Verse.Root_Play:Update ()