One to Many Core Data binding issues - objective-c

Question

I have 2 Core Data objects. Items and TimeLog. The items object has a one to many relation with TimeLog and I am using the IB and Array Controller to automatically populate the 2 NSTableView's
The top table view is for the items. When you select an item the bottom table should populate with the time logs.
However when I add an item, the application crashes with an error
<_NSFaultingMutableSet 0x102e0e790> addObserver:forKeyPath:options:context:] is not supported. Key path: date
I am using an Array Controller to populate all the information automatically. When I create and add and item I am not setting anything for the timeLog relationship because there is no time to add when they first add the item. The object is saving as I have logging that is triggered after the core data save event.
Items.h
#class TimeLog;
#interface Items : NSManagedObject
#property (nonatomic, retain) NSString * itemId;
#property (nonatomic, retain) NSString * title;
#property (nonatomic, retain) NSString * itemType;
#property (nonatomic, retain) NSSet *timeLog;
#end
#interface Items (CoreDataGeneratedAccessors)
- (void)addTimeLogObject:(TimeLog *)value;
- (void)removeTimeLogObject:(TimeLog *)value;
- (void)addTimeLog:(NSSet *)values;
- (void)removeTimeLog:(NSSet *)values;
#end
TimeLog.h
#class Items;
#interface TimeLog : NSManagedObject
#property (nonatomic, retain) NSString * time;
#property (nonatomic, retain) NSDate * date;
#property (nonatomic, retain) Items *item;
#end
What is causing this error and how do I get rid of it?

Answer 1

I resolved this by creating another NSArrayController for my TimeLog and setting up the table like so.
TimeLog Arra Controller
Set Controller Content -> Content Set -> Bind to Items array controller. Model Key path to timeLog
Then each column of the table.