Wrong Core Data Detail Record in Master-Detail

I defined a schema in Core Data Xcode with one-to-one detail records. In the Master Table View it displays the master records as expected. When I select a master record, it then displays a detail record, but for the wrong master. I viewed the actual data in SQLite and it looks fine. In the Master's PrepareForSegue routine the index that comes in is correct. The object selected is not. Do I need to do an additional Detail fetch?

• (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { if ([[segue identifier] isEqualToString:@"showDetail"]) {

  NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
  NSLog(@"Master: Prepare for segue indexPath: %@", indexPath);
  NSManagedObject *object = [self.fetchedResultsController objectAtIndexPath:indexPath];    
  NSLog(@"Master: Object before segue: %@", object);
   [[segue destinationViewController] setDetailItem:object];
  

  } }

Thanks!