URLSessionConfiguration's httpMaximumConnectionsPerHost not working in iOS 10?

Question

Setting this parameter doesn't affect the number of
simultaneous connections to a host. I've found the same issue on apple developer forum. It looks like a bug in iOS 10, iOS 9 works properly.

let sessionConfiguration = URLSessionConfiguration.background(withIdentifier: <identifier>)
    sessionConfiguration.httpMaximumConnectionsPerHost = 4
    sessionConfiguration.allowsCellularAccess = AppDelegate.shared.userDefaults.allowsCellularAccess
    sessionConfiguration.timeoutIntervalForRequest = 7*60
    sessionConfiguration.timeoutIntervalForResource = 24*60*60
    let session = URLSession(configuration: sessionConfiguration, delegate:self, delegateQueue: operationQueue)

Does anybody have the same problem? If there an alternative stable way to manage a queue of many uploads/downloads in background?