I know this was supposedly fixed but I'm seeing it in the latest version:
Failed to call hook 'OnCardSwipe' on plugin 'PuzzlePoints v1.4.0' (NullReferenceException: Object reference not set to an instance of an object)
at Oxide.Plugins.PuzzlePoints.OnCardSwipe (CardReader cardReader, Keycard card, BasePlayer player) [0x000ad] in <16fd014a510e41cbbad69f20ae4aad6b>:0
at Oxide.Plugins.PuzzlePoints.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x001a1] in <16fd014a510e41cbbad69f20ae4aad6b>:0
at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <87ce9ac9776a48658bc55eae6debe38b>:0
at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <b6d06fce9e044af4a6ddc8d724bd3b0b>:0
at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <b6d06fce9e044af4a6ddc8d724bd3b0b>:0