Populating CoreData with a for-loop creates memory error -am I doing it wrong?

Question

Howdy,

I have an issue with populating coredata from an XML load. From my limited knowledge it appears to be a memory issue, I am looking squarely at the managed object constructer in the for loop in the pseudo-code below!

We can assume 'myManagedStore' is a valid coredata object with an NSSet of "managedObjects" and that 'myNSSetOfItems' is a NSMutableDictionary of key/value pairs generated from my XML parse.

Note: I start debugging with the application and data deleted from the simulator.

for (NSMutableDictionary *item in myNSSetOfItems){
    MyManagedObject *managedObject = [MyManagedObject mangedObjectInContext];
    managedObject.key = item.value;
    ...
    ...


    NSLog(@"log managedObject to show me its key/value pairs here");
    [myManagedStore addManagedObject:managedObject];

}

Logging the managedObject at the store injection point shows it to be a 'MyManagedObject' with valid key/value pairs from the for-loop initialiser.

Next, I quit the app and start it again. I run a debug routine to check the contents of the store

for (MyManagedObject *managedObject in storedSet){
    // the following finds the managedObject OK
    NSLog(@"Found managedObject as %@",managedObject);
    // but accessing any properties reveals the error
    NSLog(@"A property of managedObject is %@",[managedObject myProperty]);
}

The first iteration is fine, it finds managedObject and logs correctly. The second iteration is hectic. Both random and inherently wrong - in one instance I saw it log

Found managedObject as managed/com.apple.SystemConfiguration/kCFPreferencesCurrentUser

This immediately suggests to me that I have a memory issue - it looks like my managedObject in the first code block isn't being closed or finalised correctly.. The problem is, I don't know why!

The code for [MyManagedObject mangedObjectInContext] is a simple convenience routine in the managed object, I have had no previous issues with this approach

+ (id)managedObjectInContext:(NSManagedObjectContext*)context {
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"ManagedObject" inManagedObjectContext:context];
    ManagedObject *managedObject = [[ManagedObject alloc] initWithEntity:entity insertIntoManagedObjectContext:context];
    return [managedObject autorelease];
}

Sorry if the question is dumb, I am new to ObjC and iOs development.