Problems with Qml+QtConcurrency on imx.6

[r3d9u11]

Hello.
I've noted the different behavior of the same application on different platforms: x86_64 and ARM (imx6).

I tried to call some parallel logic from event handler of QML.

On x86_64 all works fine and clear.
But on ARM QtConcurrency doesn't fire the body of function, BUT in the same time isStarted() and isRunning() both return 'true'.

For example:
main.qml

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")
    Component.onCompleted: NMgr.callOnAppWindowCompleted()
    onClosing: NMgr.callOnAppWindowClosed()

    Shortcut { sequence: "Ctrl+q"; onActivated: NMgr.callOnUserEvent() }
}

appnative.h

class AppNative: public QObject
{
    bool pflg = false;
    QFuture<void> plf;
    QFuture<void> pmf;
    QFuture<void> puf;

    QTimer* tlf;
    QTimer* tmf;

Q_OBJECT public:

    explicit AppNative();
    virtual ~AppNative();

    Q_INVOKABLE void callOnAppWindowCompleted();
    Q_INVOKABLE void callOnAppWindowClosed();
    Q_INVOKABLE void callOnUserEvent();

private:

    void parallelMemberFunc();
    void timerMemberFunc();
};

appnative.cpp

AppNative::AppNative()
{
    tlf = new QTimer(this);
    tmf = new QTimer(this);

    auto timerLambdaFunc = [&]() {
        qDebug() << "      1000: Hello from timer lambda function!";
    };

    connect(tlf, &QTimer::timeout, this, timerLambdaFunc);
    connect(tmf, &QTimer::timeout, this, &AppNative::timerMemberFunc);
}

AppNative::~AppNative()
{
    plf.~QFuture();
    pmf.~QFuture();

    tlf->~QTimer();
    tmf->~QTimer();
}

void AppNative::parallelMemberFunc()
{
    while (pflg) {
        qDebug() << "   500: Hello from parallel member function!";
        QThread::msleep(500);
    }
}

void AppNative::timerMemberFunc()
{
    qDebug() << "         2000: Hello from timer member function!";
}

void AppNative::callOnAppWindowCompleted()
{
    auto parallelLambdaFunc = [&]() {
        while (pflg) {
            qDebug() << "250: Hello from parallel lambda function!";
            QThread::msleep(250);
        }
    };

    pflg = true;
    plf  = QtConcurrent::run(parallelLambdaFunc);
    pmf  = QtConcurrent::run(this, &AppNative::parallelMemberFunc);

    tlf->start(1000);
    tmf->start(2000);
}

void AppNative::callOnAppWindowClosed()
{
    pflg = false;
    plf.waitForFinished();
    pmf.waitForFinished();

    tlf->stop();
    tmf->stop();
}

void AppNative::callOnUserEvent()
{
    qDebug() << "Try to run parallel event handler...";
    puf = QtConcurrent::run([] { qDebug() << "--> Hello from parallel event handler..."; });
}

x86_64 output:

250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
Try to run parallel event handler...
--> Hello from parallel event handler...
         2000: Hello from timer member function!
      1000: Hello from timer lambda function!
   500: Hello from parallel member function!
250: Hello from parallel lambda function!
Try to run parallel event handler...
--> Hello from parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
--> Hello from parallel event handler...
   500: Hello from parallel member function!
250: Hello from parallel lambda function!
Try to run parallel event handler...
--> Hello from parallel event handler...
...

ARM:

250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
      1000: Hello from timer lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
      1000: Hello from timer lambda function!
250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
         2000: Hello from timer member function!
      1000: Hello from timer lambda function!
250: Hello from parallel lambda function!
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
      1000: Hello from timer lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
Try to run parallel event handler...
250: Hello from parallel lambda function!
...
...

There were missed calls of parallel method with message"500:..." and parallel handler of user's event (hotkey Ctrl+q).
In more complex application the same problem rise more often.

Could anybody clarify, what I'm doing wrong?
Why there is different behavior of the same application on different platforms?

I can share full project of this simple test application.

Thanks!

[r3d9u11]

@r3d9u11 seems like related to resources limitations.
if try to change QThreadPool::globalInstance()->setMaxThreadCount and set needed thread count, all work fine.