Remove from equip before changing slot.

src/engine/net/client/handlers/TransferItemFromEquipToInventoryHandler.java

@@ -58,8 +58,10 @@ public class TransferItemFromEquipToInventoryHandler extends AbstractClientMsgHa
         if (!item.validForEquip(origin, player, itemManager))
             return true;
 
-        if (item.containerType == Enum.ItemContainerType.EQUIPPED)
+        if (item.containerType == Enum.ItemContainerType.EQUIPPED) {
+            itemManager.equipped.remove(item.equipSlot);
             itemManager.moveItemToInventory(item);
+        }
 
         int ItemType = item.getObjectType().ordinal();
         int ItemID = item.getObjectUUID();