qt6 sigsegv with QString::fromUtf16

#include <QCoreApplication>
#include <QString>
#include <QDebug>

static const int8_t g_test[12] = { 0x48, 0x0, 0x48, 0x0, 0x0, 0x48, 0x0, 0x48, 0x0, 0x0, 0x0 };

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

    const char* str = (const char*) g_test;
    auto t1 = QString::fromUtf16((const char16_t*) str);

    str += 7;

    // sigsegv
    auto t2 = QString::fromUtf16((const char16_t*) str);

    qDebug() << t1;
    qDebug() << t2;

    return a.exec();
}