return no longLived CKOperation

Question

1. I created a CKOperation whose longLived was set "true".
2. Turn on flight mode for my iPhone(iOS 9.3.5)
3. kill app

4. relaunch, and found no longLived operations

   [[CKContainer defaultContainer] fetchAllLongLivedOperationIDsWithCompletionHandler:^(NSArray<NSString *> * _Nullable outstandingOperationIDs, NSError * _Nullable error) {
   if (error) {
       NSLog(@"----------error---  %@", error);
   }else {
       NSLog(@"outstandingOperationIDs: %@", outstandingOperationIDs);  **// always return ()**
   }
   }];