getting this error in console

Failed to call hook 'OnEntityDeath' on plugin 'ClaimRewards v2.0.9' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.ClaimRewards.IncKillsAndCheckIfReward (BasePlayer player) [0x00000] in <058411121db8499287cfc62d8ceb749f>:0
  at Oxide.Plugins.ClaimRewards.OnEntityDeath (BaseCombatEntity entity, HitInfo info) [0x00112] in <058411121db8499287cfc62d8ceb749f>:0
  at Oxide.Plugins.ClaimRewards.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x001c9] in <058411121db8499287cfc62d8ceb749f>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <23ba99f131254889867c71f0bd137b1d>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <157a94ee66ab4a7991faecd1eb84be3b>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <157a94ee66ab4a7991faecd1eb84be3b>:0

I've done a quick check and see no issues?

nor any changes to the OnEntityDeath hook?

did you update oxide to the latest version?