Failed to call hook 'OnItemCraft' on plugin 'CraftingController v3.2.9' (NullReferenceException: Object reference not set to an instance of an object)
  at Item.OnChanged () [0x0001d] in <3e15ca7896a1410db6d120bc00d1300d>:0

  at Item.MarkDirty () [0x00000] in <3e15ca7896a1410db6d120bc00d1300d>:0

  at Item.set_maxCondition (System.Single value) [0x00029] in <3e15ca7896a1410db6d120bc00d1300d>:0

  at Item.Initialize (ItemDefinition template) [0x00015] in <3e15ca7896a1410db6d120bc00d1300d>:0

  at ItemManager.Create (ItemDefinition template, System.Int32 iAmount, System.UInt64 skin) [0x00065] in <3e15ca7896a1410db6d120bc00d1300d>:0

  at Oxide.Plugins.CraftingController.InstantBulkCraft (BasePlayer player, ItemCraftTask task, ItemDefinition item, System.Collections.Generic.List`1[T] stacks, System.Int32 craftSkin, System.UInt64 skin) [0x00028] in <29db957461e04c27a247a5acfa71ea9f>:0

  at Oxide.Plugins.CraftingController.OnItemCraft (ItemCraftTask task, BasePlayer player) [0x000d4] in <29db957461e04c27a247a5acfa71ea9f>:0

  at Oxide.Plugins.CraftingController.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0022a] in <29db957461e04c27a247a5acfa71ea9f>: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 <18d4f19bbc844191b11ed9e69284d09b>:0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <18d4f19bbc844191b11ed9e69284d09b>:0

I am looking into this to see what to do to fix it. Maybe youll get it before me haha or have an idea. 

Does it happen often if so I can give you a debug version

I ended up fixing the onitemcraft. It is now not giving the issue. Just wanted to let you know. It was doing it every time anyone crafted something. I was away for a bit and apoligize for not getting back sooner.

Do you know what was causing the issue ?

private object OnItemCraft(ItemCraftTask task, BasePlayer player)
{
var target = task.blueprint.targetItem;
if (task == null || task?.instanceData?.dataInt != null || task?.amount == 0) return null;
var stacks = GetStacks(target, task.amount * task.blueprint.amountToCreate);
ulong defaultskin = 0uL;
int freeslots = FreeSlots(player);
bool f = false;
if (!config.FullInventory && stacks.Count >= freeslots)
{
f = true;
int space = FreeSpace(player, target);
if (space < 1)
{
ReturnCraft(task, player);
return false;
}
int taskamt = task.amount * task.blueprint.amountToCreate;
for (int i = 0; i < 20 && taskamt > space; i++)
{
var oldtaskamt = taskamt;
taskamt = space;
foreach (var item in task.takenItems)
{
var itemtogive = item;
double fraction = (double)taskamt / (double)oldtaskamt;
int amttogive = (int)(item.amount * (1 - fraction));
if (amttogive <= 1)
{
ReturnCraft(task, player);
return false;
}
itemtogive = ItemManager.Create(item.info, amttogive, 0uL);
item.amount -= amttogive;

player.GiveItem(itemtogive);
}
space -= (freeslots - FreeSlots(player)) * target.stackable;
if (space < 1 || taskamt < 1)
{
ReturnCraft(task, player);
return false;
}
if (taskamt <= space) break;

}
task.amount = (int)(taskamt / task.blueprint.amountToCreate);
}

if (task.skinID == 0)
{
CraftingData data;
if (config.CraftingOptions.TryGetValue(target.shortname, out data))
{
defaultskin = data.defaultskinid;
}

if (config.RandomSkins && defaultskin == 0)
{
List<ulong> skins = GetSkins(ItemManager.FindItemDefinition(target.itemid));
defaultskin = skins.GetRandom();
}

if (defaultskin > 999999)
skinupdate[task] = defaultskin;
else
task.skinID = (int)defaultskin;
}

float bonusperm_time = float.MaxValue;
foreach (var bonusperm in permissionsBonusMultiplier)
{
if (!HasPerm(player.UserIDString, $"{bonusperm}")) continue;
if (bonusperm_time < (float)config.BonusMultiplier[bonusperm.Split('.')[1]]) continue;
bonusperm_time = (float)config.BonusMultiplier[bonusperm.Split('.')[1]];
}
if(bonusperm_time != float.MaxValue)
{
task.blueprint = UnityEngine.Object.Instantiate(task.blueprint);
task.blueprint.time *= bonusperm_time / 100;
}

if (task.blueprint.time == 0f || HasPerm(player.UserIDString, perminstantbulkcraft))
{
skinupdate.Remove(task);
if (f)
stacks = GetStacks(target, task.amount * task.blueprint.amountToCreate);
InstantBulkCraft(player, task, target, stacks, task.skinID, defaultskin);
task.cancelled = true;
return false;
}
return null;
}

This is what I ended up doing. This fixed it.

Merged post

Sorry for late replies.. Life has been hell atm.