NSManagedObject's hasChanges is true while changedValues is empty

I am trying to observe individual NSManagedObject changes on NSManagedObjectContextWillSaveNotification:

- (void)managedObjectContextWillSave:(NSNotification *)notification
{
    for (NSManagedObject * object in self.mutableObservedManagedObjects)
    {
        if (object.hasChanges)
        {
            [self managedObjectWasUpdated:object];
        }
    }
}

The problem is that hasChanges is true while object.changedValues is empty, thus wrongly (?) triggering managedObjectWasUpdated:.

I'm trying to understand why this is the case and if I should better check object.changedValues.count before calling managedObjectWasUpdated:.

isInserted and isDeleted are both false.

I encountered the same issue. Instead of getting the flags, I just checked if changedValues() is empty.

For Swift:

if !managedObject.changedValues().isEmpty {
    // Has some changed values
}