diff --git a/Facepunch.Steamworks/Interfaces/Inventory.Item.cs b/Facepunch.Steamworks/Interfaces/Inventory.Item.cs
index 84c4383..cbda47d 100644
--- a/Facepunch.Steamworks/Interfaces/Inventory.Item.cs
+++ b/Facepunch.Steamworks/Interfaces/Inventory.Item.cs
@@ -55,19 +55,19 @@ public Definition Definition
 
             public bool TradeLocked;
 
-            public bool Equals( Item other )
+            public bool Equals(Item other)
             {
-                return Equals( other, this );
+                if (ReferenceEquals(null, other)) return false;
+                if (ReferenceEquals(this, other)) return true;
+                return Id == other.Id;
             }
 
-            public override bool Equals( object obj )
+            public override bool Equals(object obj)
             {
-                if ( obj == null || GetType() != obj.GetType() )
-                {
-                    return false;
-                }
-
-                return ((Item)obj).Id == Id;
+                if (ReferenceEquals(null, obj)) return false;
+                if (ReferenceEquals(this, obj)) return true;
+                if (obj.GetType() != this.GetType()) return false;
+                return Equals((Item)obj);
             }
 
             public override int GetHashCode()
@@ -75,15 +75,14 @@ public override int GetHashCode()
                 return Id.GetHashCode();
             }
 
-
-            public static bool operator ==( Item c1, Item c2 )
+            public static bool operator ==(Item left, Item right)
             {
-                return c1.Equals( c2 );
+                return Equals(left, right);
             }
 
-            public static bool operator !=( Item c1, Item c2 )
+            public static bool operator !=(Item left, Item right)
             {
-                return !c1.Equals( c2 );
+                return !Equals(left, right);
             }
 
             /// <summary>
diff --git a/Facepunch.Steamworks/Interfaces/Inventory.Result.cs b/Facepunch.Steamworks/Interfaces/Inventory.Result.cs
index 68935bb..129f64f 100644
--- a/Facepunch.Steamworks/Interfaces/Inventory.Result.cs
+++ b/Facepunch.Steamworks/Interfaces/Inventory.Result.cs
@@ -114,6 +114,10 @@ internal void Fill()
                 for ( int i=0; i< steamItems.Length; i++ )
                 {
                     var item = inventory.ItemFrom( Handle, steamItems[i], i );
+                    if ( item == null )
+                    {
+                        continue;
+                    }
 
                     if ( ( steamItems[i].Flags & (int)SteamNative.SteamItemFlags.Removed ) != 0 )
                     {
@@ -189,6 +193,13 @@ internal Item ItemFrom( SteamInventoryResult_t handle, SteamItemDetails_t detail
                 {
                     if ( inventory.GetResultItemProperty(handle, (uint)index, propertyName, out string propertyValue ) )
                     {
+                        if (propertyName == "error")
+                        {
+                            Console.Write("Steam item error: ");
+                            Console.WriteLine(propertyValue);
+                            return null;
+                        }
+
                         props.Add(propertyName, propertyValue);
                     }
                 }
diff --git a/Facepunch.Steamworks/Interfaces/Inventory.cs b/Facepunch.Steamworks/Interfaces/Inventory.cs
index c0517e3..d3b34e5 100644
--- a/Facepunch.Steamworks/Interfaces/Inventory.cs
+++ b/Facepunch.Steamworks/Interfaces/Inventory.cs
@@ -129,14 +129,14 @@ private void onResultReady( SteamInventoryResultReady_t data )
             }
         }
 
-        private void onResult( Result r, bool serialize )
+        private void onResult( Result r, bool isFullUpdate )
         {
             if ( r.IsSuccess )
             {
                 //
                 // We only serialize FULL updates
                 //
-                if ( serialize )
+                if ( isFullUpdate )
                 {
                     //
                     // Only serialize if this result is newer than the last one
@@ -149,7 +149,7 @@ private void onResult( Result r, bool serialize )
                 }
 
                 LastTimestamp = r.Timestamp;
-                ApplyResult( r );
+                ApplyResult( r, isFullUpdate );
             }
 
             r.Dispose();
@@ -161,7 +161,7 @@ private void onResult( Result r, bool serialize )
         /// Here we're trying to keep our stack up to date with whatever happens
         /// with the crafting, stacking etc
         /// </summary>
-        internal void ApplyResult( Result r )
+        internal void ApplyResult( Result r, bool isFullUpdate )
         {
             if ( IsServer ) return;
 
@@ -170,12 +170,19 @@ internal void ApplyResult( Result r )
                 if ( Items == null )
                     Items = new Item[0];
 
-                Items = Items
-                        .Union( r.Items )
-                        .Distinct()
-                        .Where( x => !r.Removed.Contains( x ) )
-                        .Where( x => !r.Consumed.Contains( x ) )
+                if (isFullUpdate)
+                {
+                    Items = r.Items;
+                }
+                else
+                {
+                    // keep the new item instance because it might have a different quantity, properties, etc
+                    Items = Items
+                        .UnionSelect(r.Items, (oldItem, newItem) => newItem)
+                        .Where(x => !r.Removed.Contains(x))
+                        .Where(x => !r.Consumed.Contains(x))
                         .ToArray();
+                }
 
                 //
                 // Tell everyone we've got new items!
diff --git a/Facepunch.Steamworks/Utility.cs b/Facepunch.Steamworks/Utility.cs
index 1bb7e43..86e70e3 100644
--- a/Facepunch.Steamworks/Utility.cs
+++ b/Facepunch.Steamworks/Utility.cs
@@ -94,6 +94,28 @@ public static string ReadNullTerminatedUTF8String( this BinaryReader br, byte[]
 
             return Encoding.UTF8.GetString( buffer, 0, i );
         }
-        
+
+        public static IEnumerable<T> UnionSelect<T>(
+            this IEnumerable<T> first,
+            IEnumerable<T> second,
+            Func<T, T, T> selector) where T : IEquatable<T>
+        {
+            var items = new Dictionary<T, T>();
+
+            foreach (var i in first)
+            {
+                items[i] = i;
+            }
+
+            foreach (var i in second)
+            {
+                T firstValue;
+                if (items.TryGetValue(i, out firstValue))
+                {
+                    items.Remove(i);
+                    yield return selector(firstValue, i);
+                }
+            }
+        }
     }
 }