translations are totally broken in qt 5.11.1

// test/test.qbs
import qbs
import qbs.FileInfo

Project {
    minimumQbsVersion: "1.7.1"

    references: [
        "translations"
    ]

    CppApplication {
        Depends {
            name: "Qt"
            submodules: [
                "core",
                "quick",
                "gui",
                "quickcontrols2",
                "widgets"
                "qml"
            ]
        }

        name: "test"

        cpp.cxxLanguageVersion: "c++11"

        files: [
            "*.cpp",
            "*.qrc",
        ]

        Group {
            fileTagsFilter: "application"
            qbs.install: true
        }
    }
}

// test/translations/translations.qbs
import qbs 1.0

Product {
    name: "translations"
    type: "qm"
    files: "*.ts"

    Depends { name: "Qt.core" }

    Group {
        fileTagsFilter: product.type
        qbs.install: true
        qbs.installDir: product.name
    }
}

// test/main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QTranslator>
#include <QDebug>
#include <iostream>

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QGuiApplication app(argc, argv);


    const QString translationFilename = qApp->applicationDirPath() +
            "translations/test_rus.qm";
    qDebug() << "translation file is" << translationFilename;

    QTranslator translator;

    if(translator.load(translationFilename))
    {
        qDebug() << "translation file loaded";

        if(qApp->installTranslator(&translator))
            qDebug() << "translator installed";
        else
            qDebug() << "failed to install translator";
    }
    else
    {
        qDebug() << "loading of translation file failed";
    }

    qDebug() << QObject::tr("test from cpp");
    std::cout << QObject::tr("qDebug doesn't work here").toStdString()
              << std::endl << std::flush;

    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

// test/main.qml
import QtQuick 2.11
import QtQuick.Window 2.11

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")
}

// shell from test
lupdate . -ts translations/test_rus.ts
linguist translations/test_rus.ts