QMultiHash::insert() does not return a correct iterator to the inserted element

struct key {
    bool operator==(const key& other) const {
        return x == other.x;
    }
    int x = 0;
    int y = 0;
};

inline size_t qHash(const key& k) {
    return qHash(k.x);
}
template<>
struct std::hash<key>
{
    std::size_t operator()(const key& k) const noexcept
    {
        return qHash(k);
    }
};

int main(int argc, char* argv[])
{
    qDebug() << "QMultiHash";
    {
        QMultiHash<key, int> m;
        m.insert({ 1, 1 }, 1);
        auto it = m.insert({ 1, 2 }, 2);
        qInfo() << "Key:" << it.key().x << it.key().y << ", value: " << it.value();
        qInfo() << "Dumping container:";
        for (auto it = m.begin(); it != m.end(); ++it) {
            qInfo() << "Key:" << it.key().x << it.key().y << ", value: " << it.value();
        }
    }
    qDebug() << "";
    qDebug() << "std::unordered_multimap";
    {
        std::unordered_multimap<key, int> u;
        u.insert(std::make_pair<key, int>({ 1, 1 }, 1));
        auto it = u.insert(std::make_pair<key, int>({ 1, 2 }, 2));
        qInfo() << "Key:" << it->first.x << it->first.y << ", value: " << it->second;
        qInfo() << "Dumping container:";
        for (auto it = u.begin(); it != u.end(); ++it) {
            qInfo() << "Key:" << it->first.x << it->first.y << ", value: " << it->second;
        }
    }
    return 0;
}