Why text layout eats letters when dealing with non-breakable spaces?

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Test code (Qt5.5.1):

#include <QApplication>
#include <QMainWindow>
#include <QTextBrowser>
 
int main(int argc, char* argv[])
{
    QApplication a(argc, argv);    
 
    QTextBrowser* textBrowser = new QTextBrowser();
    textBrowser->setHtml("<p style=\"font-size: 50pt\">X АБ&nbsp;Y</p>");
 
    QMainWindow w;
    w.setCentralWidget(textBrowser);
    w.resize(200, 200);
    w.show();
 
    return a.exec();
}

#include <QApplication>
#include <QMainWindow>
#include <QTextBrowser>

int main(int argc, char* argv[])
{
    QApplication a(argc, argv);    

    QTextBrowser* textBrowser = new QTextBrowser();
    textBrowser->setHtml("<p style=\"font-size: 50pt\">X АБ&nbsp;Y</p>");

    QMainWindow w;
    w.setCentralWidget(textBrowser);
    w.resize(200, 200);
    w.show();

    return a.exec();
}

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Result:
error.png

How can I avoid non-ascii letters (like 'А' in test) followed by text with   disappearing?