Getting a weird bug, presumably from an interaction with another mod. It messes up caravans and trade with industrial factions to the point where I cannot trade.

System.InvalidOperationException: Sequence contains no elements
at System.Linq.Enumerable.First[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x00010] in <351e49e2a5bf4fd6beabb458ce2255f3>:0
at RimWorld.GenStuff.DefaultStuffFor (Verse.BuildableDef bd) [0x00145] in <f51597c720ac4bec9b4bfc9070cc723e>:0
at RimWorld.StockGenerator_Armor.HandlesThingDef (Verse.ThingDef td) [0x00014] in <f51597c720ac4bec9b4bfc9070cc723e>:0
at RimWorld.TraderKindDef.WillTrade (Verse.ThingDef td) [0x00010] in <f51597c720ac4bec9b4bfc9070cc723e>:0
at RimWorld.Dialog_SellableItems.CalculateSellableItems (RimWorld.TraderKindDef trader) [0x00068] in <f51597c720ac4bec9b4bfc9070cc723e>:0
at RimWorld.Dialog_SellableItems..ctor (RimWorld.ITrader trader) [0x00058] in <f51597c720ac4bec9b4bfc9070cc723e>:0
at RimWorld.Planet.Settlement.<GetGizmos>b__61_0 () [0x00005] in <f51597c720ac4bec9b4bfc9070cc723e>:0
at Verse.Command_Action.ProcessInput (UnityEngine.Event ev) [0x00007] in <f51597c720ac4bec9b4bfc9070cc723e>:0
at Verse.GizmoGridDrawer.DrawGizmoGrid (System.Collections.Generic.IEnumerable`1[T] gizmos, System.Single startX, Verse.Gizmo& mouseoverGizmo, System.Func`2[T,TResult] customActivatorFunc, System.Func`2[T,TResult] highlightFunc, System.Func`2[T,TResult] lowlightFunc) [0x006a6] in <f51597c720ac4bec9b4bfc9070cc723e>:0
at (wrapper dynamic-method) RimWorld.InspectGizmoGrid.RimWorld.InspectGizmoGrid.DrawInspectGizmoGridFor_Patch0(System.Collections.Generic.IEnumerable`1<object>,Verse.Gizmo&)
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) Verse.Log:Verse.Log.Error_Patch3 (string)
Verse.Log:ErrorOnce (string,int)
(wrapper dynamic-method) RimWorld.InspectGizmoGrid:RimWorld.InspectGizmoGrid.DrawInspectGizmoGridFor_Patch0 (System.Collections.Generic.IEnumerable`1<object>,Verse.Gizmo&)
RimWorld.Planet.WorldInspectPane:DrawInspectGizmos ()
RimWorld.InspectPaneUtility:ExtraOnGUI (RimWorld.IInspectPane)
RimWorld.Planet.WorldInspectPane:ExtraOnGUI ()
Verse.WindowStack:WindowStackOnGUI ()
(wrapper dynamic-method) RimWorld.UIRoot_Play:RimWorld.UIRoot_Play.UIRootOnGUI_Patch2 (RimWorld.UIRoot_Play)
(wrapper dynamic-method) Verse.Root:Verse.Root.OnGUI_Patch1 (Verse.Root)