Summary

Using QTimeZone(Qt::UTC) results in an invalid offset of +1 second, causing incorrect QDateTime values when used in time zone conversions.

Reproduction Code

auto dateTime = QDateTime::currentDateTime();
auto actualDateTime1 = dateTime;
actualDateTime1.setTimeZone(QTimeZone(Qt::UTC));
qDebug() << "Actual DateTime 1:" << actualDateTime1;
auto actualDateTime2 = dateTime;
actualDateTime2.setTimeZone(QTimeZone("UTC"));
qDebug() << "Actual DateTime 2:" << actualDateTime2;

Observed Output

Actual DateTime 1: QDateTime(2025-08-04 00:13:36.973 UTC+00:00:01 Qt::TimeZone UTC+00:00:01)
Actual DateTime 2: QDateTime(2025-08-04 00:13:36.973 UTC Qt::TimeZone UTC)

Expected Output

Both conversions should produce the same result — with UTC+00:00:00.

Workaround

Use QTimeZone("UTC") instead of QTimeZone(Qt::UTC).