I think there may be a problem with a specific weapon (probably one from another mod).
Never had trouble with the button before, after a raid where I got a bunch of new weapons clicking the button logs

Root level exception in OnGUI(): System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object
at WeaponStats.MainTabWindow_WeaponStats+<>c.<.ctor>b__54_0 (Verse.ModMetaData m) [0x00000] in <c5bb221a73734fe6b6dcf553aae007f1>:0
at System.Linq.Enumerable.Any[TSource] (System.Collections.Generic.IEnumerable`1[T] source, System.Func`2[T,TResult] predicate) [0x0002c] in <351e49e2a5bf4fd6beabb458ce2255f3>:0
at WeaponStats.MainTabWindow_WeaponStats..ctor () [0x0007d] in <c5bb221a73734fe6b6dcf553aae007f1>:0
at (wrapper managed-to-native) System.Reflection.MonoCMethod.InternalInvoke(System.Reflection.MonoCMethod,object,object[],System.Exception&)
at System.Reflection.MonoCMethod.InternalInvoke (System.Object obj, System.Object[] parameters) [0x00002] in <eae584ce26bc40229c1b1aa476bfa589>:0
--- End of inner exception stack trace ---
at System.Reflection.MonoCMethod.InternalInvoke (System.Object obj, System.Object[] parameters) [0x00014] in <eae584ce26bc40229c1b1aa476bfa589>:0
at System.RuntimeType.CreateInstanceMono (System.Boolean nonPublic) [0x000a8] in <eae584ce26bc40229c1b1aa476bfa589>:0
at System.RuntimeType.CreateInstanceSlow (System.Boolean publicOnly, System.Boolean skipCheckThis, System.Boolean fillCache, System.Threading.StackCrawlMark& stackMark) [0x00009] in <eae584ce26bc40229c1b1aa476bfa589>:0
at System.RuntimeType.CreateInstanceDefaultCtor (System.Boolean publicOnly, System.Boolean skipCheckThis, System.Boolean fillCache, System.Threading.StackCrawlMark& stackMark) [0x00027] in <eae584ce26bc40229c1b1aa476bfa589>:0
at System.Activator.CreateInstance (System.Type type, System.Boolean nonPublic) [0x00020] in <eae584ce26bc40229c1b1aa476bfa589>:0
at System.Activator.CreateInstance (System.Type type) [0x00000] in <eae584ce26bc40229c1b1aa476bfa589>:0
at RimWorld.MainButtonDef.get_TabWindow () [0x00016] in <3126aca1aad041dcbdeda807cfe004bf>:0
at (wrapper dynamic-method) RimWorld.MainTabsRoot.RimWorld.MainTabsRoot.ToggleTab_Patch2(RimWorld.MainTabsRoot,RimWorld.MainButtonDef,bool)
at RimWorld.MainButtonWorker_ToggleTab.Activate () [0x00005] in <3126aca1aad041dcbdeda807cfe004bf>:0
at UINotIncluded.Widget.Workers.Button_Worker.InterfaceTryActivate () [0x00098] in <1f9bbb5621134239a65cb9fb2fff5ef1>:0
at UINotIncluded.Widget.Workers.Button_Worker.OnInteraction (UnityEngine.Rect rect) [0x0003c] in <1f9bbb5621134239a65cb9fb2fff5ef1>:0
at UINotIncluded.Widget.Workers.Button_Worker.OnGUI (UnityEngine.Rect rect) [0x0001a] in <1f9bbb5621134239a65cb9fb2fff5ef1>:0
at UINotIncluded.Widget.ExtendedToolbar.ExtendedToolbarOnGUI (System.Collections.Generic.List`1[T] elements, UnityEngine.Rect inRect) [0x00105] in <1f9bbb5621134239a65cb9fb2fff5ef1>:0
at UINotIncluded.UIManager.BarsOnGUI () [0x0004a] in <1f9bbb5621134239a65cb9fb2fff5ef1>:0
at (wrapper dynamic-method) RimWorld.MainButtonsRoot.RimWorld.MainButtonsRoot.MainButtonsOnGUI_Patch2(RimWorld.MainButtonsRoot)
at (wrapper dynamic-method) RimWorld.UIRoot_Play.RimWorld.UIRoot_Play.UIRootOnGUI_Patch2(RimWorld.UIRoot_Play)
at (wrapper dynamic-method) Verse.Root.Verse.Root.OnGUI_Patch2(Verse.Root)
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) Verse.Log:Verse.Log.Error_Patch2 (string)
(wrapper dynamic-method) Verse.Root:Verse.Root.OnGUI_Patch2 (Verse.Root)