QStringList update elements during iteration circle: RuntimeError::unaligned memory acess

QStringList m_userList;
m_userList.append("AnyUser1");
QStringList userList(m_userList);
for (QString &user : userList)
{
    user = user + " AnyName1";
}
userList.push_front("AnyUser0");

QStringList m_userList;
m_userList.append("AnyUser1");
QStringList userList(m_userList);
for (int i = 0; i < userList.size(); i++)
{
    QString user = userList[i];
    user = user + " AnyName1";
    userList[i] = user;
}
userList.push_front("AnyUser0");