Hi there I have a few times this message in console:

00:01 [Error] Failed to call hook 'OnEntityKill' on plugin 'ZoneManager v3.0.23' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.ZoneManager+Zone.OnEntityExitZone (BaseEntity baseEntity, System.Boolean resetDecay, System.Boolean isDead) [0x00000] in <6032ac0f8e6040f1be038fd042382409>:0 
  at Oxide.Plugins.ZoneManager.OnEntityKill (BaseEntity baseEntity) [0x00062] in <6032ac0f8e6040f1be038fd042382409>:0 
  at Oxide.Plugins.ZoneManager.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00874] in <6032ac0f8e6040f1be038fd042382409>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <60c318df79ed41688ea59335e48d61ad>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <dfcb48ea05694263bbc08e62a39c274c>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <dfcb48ea05694263bbc08e62a39c274c>:0