QDateTime needs clarifications on Windows

This code snippet shows that 01.01.2014 0:00:00 is an invalid date/time in 'Europe/Moscow' time zone:

    const QDateTime yearStart(QDate(2014, 1, 1));
    Q_ASSERT(yearStart.isValid()); // Fails!

But actually, it was perfectly valid date/time
And due to recent time zone data update in Russia, Microsoft has issued a patch. I examined new time zone data with http://www.southsoftware.com/tzedit.zip

The time zone update consists of -1 hour shift on 26.10.2014, 03:00:00. From +4 hours to +3.

Old time zone data was: UTC bias +4 hours, no DST.
New time zone data in Windows for year 2014 in Moscow is:
UTC bias is +3 hours.
Enable DST from 01.01.2014 0:00:00 to 26.10.2014 03:00 (add +1 hour).

And I think it's buggy because it makes 01.01.2014 0:00:00 an invalid date/time.

Consider UTC date/time 31.12.2013 19:59:59. In Moscow, it is 31.12.2013 23:59:59. The question is: what datetime will be in Moscow the next second?
It cannot be 01.01.2014 01:00:00, because that would make time difference +5 hours. It should be 01.01.2014 00:00:00!

In addition, consider:

    const char* tzMoscow = "Europe/Moscow";
    QTimeZone moscow(QByteArray::fromRawData(tzMoscow, 13));
    Q_ASSERT(moscow.isValid());
    QDateTime t1(QDate(2013, 12, 31), QTime(19, 59, 59), Qt::UTC);
    QDateTime t2 = t1.toTimeZone(moscow);
    QDateTime t3 = t1.toLocalTime(); // in 'Europe/Moscow'
    QDateTime t4 = t2.addSecs(1);
    QDateTime t5 = t3.addSecs(1);
    QTimeZone tz1 = t1.timeZone();
    QTimeZone tz2 = t2.timeZone();
    QTimeZone tz3 = t3.timeZone();

The debugger shows:
t1 == Tue Dec 31 19:59:59 2013 GMT
t2 == Tue Dec 31 23:59:59 2013 GMT
t3 == Tue Dec 31 22:59:59 2013
t4 == Wed Jan 1 00:00:00 2014 GMT
t5 == Tue Dec 31 23:00:00 2013
tz1 == "UTC"
tz2 == "Europe/Moscow"
tz3 == "Europe/Moscow"

But time difference between t1, t2 and t3 is zero.
The question is: why ::toTimeZone and ::toLocalTime produce different results? The local time zone is set to "Europe/Moscow".