I was in the shop immediately after the second round of encounters when I tried transferring a +1 Runestone from a Javelin to a Thrower's Bandolier and my game crashed, generating this error report:

System.NullReferenceException: Object reference not set to an instance of an object.
at Dawnsbury.Core.Mechanics.Treasure.Item.WithModification(ItemModification itemModification) in C:\src\dawnsbury-days\Maingame\Core\Mechanics\Treasure\Item.cs:line 426
at Dawnsbury.Mods.Creatures.RoguelikeMode.Patches.HarmonyPatches.<>c__DisplayClass8_0.<AttachSubitemPatch>b__7()
at Dawnsbury.Display.DragAndDrop.ItemSlotReceptacle.<>c__DisplayClass4_0.<Receive>b__1(Nullable`1 _) in C:\src\dawnsbury-days\Maingame\Display\DragAndDrop\ItemSlotReceptacle.cs:line 241
at Dawnsbury.Display.DragAndDrop.ItemSlotReceptacle.<>c__DisplayClass4_1.<Receive>b__3() in C:\src\dawnsbury-days\Maingame\Display\DragAndDrop\ItemSlotReceptacle.cs:line 60
at Dawnsbury.Core.Mechanics.Rules.RunestoneRules.<>c__DisplayClass5_0.<DetachSubItem>g__Detach|2() in C:\src\dawnsbury-days\Maingame\Core\Mechanics\Rules\RunestoneRules.cs:line 292
at Dawnsbury.Core.Mechanics.Rules.RunestoneRules.<>c__DisplayClass5_0.<DetachSubItem>b__0() in C:\src\dawnsbury-days\Maingame\Core\Mechanics\Rules\RunestoneRules.cs:line 268
at Dawnsbury.Phases.NonBattlePhase.Update(Game game, Single elapsedSeconds) in C:\src\dawnsbury-days\Maingame\Phases\NonBattlePhase.cs:line 46
at Dawnsbury.Phases.Menus.CampaignMenuPhase.Update(Game game, Single elapsedSeconds) in C:\src\dawnsbury-days\Maingame\Phases\Menus\CampaignMenuPhase.cs:line 142
at Dawnsbury.Auxiliary.Root.Update(GameTime gameTime) in C:\src\dawnsbury-days\Maingame\Auxiliary\Root.cs:line 397
at Microsoft.Xna.Framework.Game.DoUpdate(GameTime gameTime)
at Microsoft.Xna.Framework.Game.Tick()
at MonoGame.Framework.WinFormsGameWindow.TickOnIdle(Object sender, EventArgs e)
at System.Windows.Forms.Application.LightThreadContext.FPushMessageLoop(msoloop uReason)
at System.Windows.Forms.Application.LightThreadContext.RunMessageLoop(msoloop reason, Boolean fullModal)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(msoloop reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(msoloop reason, ApplicationContext context)
at MonoGame.Framework.WinFormsGameWindow.RunLoop()
at MonoGame.Framework.WinFormsGamePlatform.RunLoop()
at Microsoft.Xna.Framework.Game.Run(GameRunBehavior runBehavior)
at Microsoft.Xna.Framework.Game.Run()
at Dawnsbury.DawnsburyProgram.Main(String[] args) in C:\src\dawnsbury-days\Maingame\DawnsburyProgram.cs:line 48