"QLocale::toDateTime ( const QString & string, FormatType format = LongFormat ) const" cannot return correct value

QLocale locale = QLocale(QLocale::English);
//QString dateTimeStr = QString("Monday, January 5, 2009 11:48:32 AM"); // with no blank space char after "AM", this date time str cannot be parsed correctly
QString dateTimeStr = QString("Monday, January 5, 2009 11:48:32 AM ");
 
//QDateTime value = locale.toDateTime(dateTimeStr , locale.dateTimeFormat(QLocale::LongFormat)); // this will success
QDateTime value = locale.toDateTime(dateTimeStr , QLocale::LongFormat); // cannot return right QDateTime value

QDateTime QLocale::toDateTime(const QString &string, FormatType format) const
{
    return toDateTime(string, dateFormat(format)); // "dateFormat" should be replaced by "dateTimeFormat"
}