ios – CKFetchNotificationChangesOperation返回旧通知

我正在开发一个基于CloudKit的应用程序,该应用程序使用CKSubscription通知来跟踪公共数据库的更改.每当应用程序收到推送通知时,我都会使用CKFetchNotificationChangesOperation检查通知队列,并在处理完每个通知后将其标记为：

__block NSMutableArray *notificationIds = [NSMutableArray new];

CKFetchNotificationChangesOperation *operation = [[CKFetchNotificationChangesOperation alloc] initWithPrevIoUsServerChangeToken:self.serverChangeToken];
operation.notificationChangedBlock = ^(CKNotification *notification) {
    [notificationIds addObject:notification.notificationID];
    [self processRemoteNotification:notification withCompletionHandler:completionHandler];
};

__weak CKFetchNotificationChangesOperation *operationLocal = operation;
operation.fetchNotificationChangesCompletionBlock = ^(CKServerChangeToken *serverChangeToken,NSError *operationError) {
    if (operationError) {
        NSLog(@"Unable to fetch queued notifications: %@",operationError);
    }
    else {
        self.serverChangeToken = serverChangeToken;
        completionHandler(UIBACkgroundFetchResultNewData);

        // Mark the processed notifications as read so they're not delivered again if the token gets reset.
        CKMarkNotificationsReadoperation *markReadoperation = [[CKMarkNotificationsReadoperation alloc] initWithNotificationIDsToMarkRead:[notificationIds copy]];
        [notificationIds removeAllObjects];

        markReadoperation.markNotificationsReadCoR_213_11845@pletionBlock = ^(NSArray *notificationIDsmarkedRead,NSError *operationError) {
            if (operationError) {
                NSLog(@"Unable to mark notifications read: %@",operationError);
            }
            else {
                NSLog(@"%lu notifications marked read.",(unsigned long)[notificationIDsmarkedRead count]);
            }
        };

        [[CKContainer defaultContainer] addoperation:markReadoperation];

        if (operationLocal.moreComing) {
            NSLog(@"Fetching more");
            [self checkNotificationQueueWithCompletionHandler:completionHandler];
        }
    }
};

[[CKContainer defaultContainer] addoperation:operation];

据我所知,标记通知读取将使其不会在将来的队列提取中显示,即使服务器更改标记重置为nil.相反,当每个fetch只有1或2个新的时,我会在每次获取中获得很多旧的通知.我可以从notificationType标志中检测到旧的,但我担心它们会出现.我在某处错过了一步吗？