Error Log

/SpawnPointAdd monumentname
When I run the command, I get the following error. Please tell me the cause and solution.
Also, I'm trying to add an NPC to a custom monument on a custom map, but even after setting it up, the NPC isn't spawning properly. There were no particular issues before the update. Running /SpawnPointShowPos displays the correctly set point.
NPCs at standard monuments are spawning.
This is the first time I've had a custom NPC not spawn in the past few years of using the game.

Failed to call hook 'OnEntitySpawned' on plugin 'BetterNpc v1.3.2' (NullReferenceException: Object reference not set to an instance of an object)

at Oxide.Plugins.BetterNpc+ControllerSpawnPoint.IsOtherNpc (NPCPlayer npc) [0x00024] in <4e9827c5194b46ddb1cbd0fc4c4ee1c6>:0

at Oxide.Plugins.BetterNpc+<>c__DisplayClass94_0.<OnEntitySpawned>b__0 (Oxide.Plugins.BetterNpc+ControllerSpawnPoint s) [0x00008] in <4e9827c5194b46ddb1cbd0fc4c4ee1c6>:0

at Oxide.Plugins.BetterNpcExtensionMethods.ExtensionMethods.FirstOrDefault[TSource] (System.Collections.Generic.IEnumerable`1[T] source, System.Func`2[T,TResult] predicate) [0x00010] in <4e9827c5194b46ddb1cbd0fc4c4ee1c6>:0

at Oxide.Plugins.BetterNpc.OnEntitySpawned (NPCPlayer ent) [0x00014] in <4e9827c5194b46ddb1cbd0fc4c4ee1c6>:0

at Oxide.Plugins.BetterNpc.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x006c9] in <4e9827c5194b46ddb1cbd0fc4c4ee1c6>:0

at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <42f9bedc659b4f4786eb778d3cd58968>:0

at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000de] in <d59b507fd76240e5b62228d0eae39b73>:0

at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <d59b507fd76240e5b62228d0eae39b73>:0