16:21 [Error] Failed to call hook 'OnItemAddedToContainer' on plugin 'Quests v2.2.7' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Quests.hasQuests (System.UInt64 player) [0x00000] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.Quests.OnItemAddedToContainer (ItemContainer container, Item item) [0x00048] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.Quests.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0052b] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <9affce1cd15c4ec183941adef8db1722>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <4452f821def6406d834e4149849fe7ea>:0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <4452f821def6406d834e4149849fe7ea>:0

16:21 [Error] Failed to call hook 'OnItemAddedToContainer' on plugin 'Quests v2.2.7' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Quests.hasQuests (System.UInt64 player) [0x00000] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.Quests.OnItemAddedToContainer (ItemContainer container, Item item) [0x00048] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.Quests.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0052b] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <9affce1cd15c4ec183941adef8db1722>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <4452f821def6406d834e4149849fe7ea>:0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <4452f821def6406d834e4149849fe7ea>:0

16:21 [Error] Failed to call hook 'OnItemAddedToContainer' on plugin 'Quests v2.2.7' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.Quests.hasQuests (System.UInt64 player) [0x00000] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.Quests.OnItemAddedToContainer (ItemContainer container, Item item) [0x00048] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.Quests.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0052b] in <9175763dc41f44f79205735d597ebfb8>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <9affce1cd15c4ec183941adef8db1722>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <4452f821def6406d834e4149849fe7ea>:0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <4452f821def6406d834e4149849fe7ea>:0

Yes, it spams a lot of errors, but it still works perfectly.

I have a crash once or twice a day.. Looking for anything at all causing errors.. this is the only major error spitter.. so i was just wondering

Just out of curiosity, can you post a list of your plugins please? I also have sometimes daily random crashes, but I don't use Quests at all. Just curious what plugins we share. 

I kept having at least one crash per day, with Quests being the only plugin spitting errors (Same as above, something about a container)

I disabled quests a week ago and have not had a single crash since

My players really miss the quests (PVE server) but appreciate it not crashing and kicking 40-50 players 

This error should be gone now, I hope.  Let me know as I don't recall seeing it, myself.