Strange insertion behavior to QPlainTextEdit when using stylesheet

I am noticing some strange text insertion behavior to a QPlainTextEdit widget when using a stylesheet. I'd like to use a 'fixed' font in my stylesheet. when i do this, i see that the text i want inserted 'inject' is actually missing the 'nj' characters so i end up with 'i ect' in the widget. when i use 'Courier' instead of 'fixed' font-family in the stylesheet, all is well. could it be due to my font server or problem with my environment? i don't have ready access to test on another machine outside of my environment.

here's the code:

Code:

---

#include <QtCore>
#include <QtGui>
 
//-----------------------------------------------------------
//  main
//-----------------------------------------------------------
int main (int argc, char* argv[]) {
 
    QApplication app(argc, argv);
 
    QMainWindow *main_window = new QMainWindow();
    main_window->setGeometry(100,100,800,600);
 
    //  if you use font-family: "Courier", output looks fine.  only problematic
    //  with "fixed"
    //
    app.setStyleSheet(
        "QPlainTextEdit{ font-family: \"fixed\"; }"
    );
 
    QWidget *main = new QWidget();
 
    QPlainTextEdit *text = new QPlainTextEdit();
 
    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(text);
    main->setLayout(layout);
 
    main_window->setCentralWidget(main);
 
    //  this should show 'i ect' in the text window
    //  NOTE:  'nj' chars are simply not printed
    //
    text->appendPlainText("inject");
 
    main_window->show();
 
    return app.exec();
 
}

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thoughts? sorry in advance if this is basic question.