Strange segmentation fault using vector of vector and iterators

Question

I am working with vector of vector and am accessing them with iterators. I wrote two simplified programs to illustrate my problem. One is with normal vectors, and the other is with vector of vector.

The first one works:

#include <iostream>
#include <vector>

typedef std::vector<double> Vec;

int main()
{
    Vec v({0, 1});

    std::cout << *v.begin() << " " << *(v.end()-1) << std::endl;

    Vec::iterator it = v.end()-1;

    v.push_back(2);

    std::cout << *it << " " << *(v.end()-1) << std::endl;
    return 0;
}

It outputs:

0 1
1 2

The second one looks exactly the same except v contains vectors instead of doubles.

#include <iostream>
#include <vector>

typedef std::vector<std::vector<double>> Graph;

int main()
{
    Graph v({{0, 0}, {1, 1}});

    std::cout << (*v.begin()).front() << " " << (*(v.end()-1)).front() << std::endl;

    Graph::iterator it = v.end()-1;

    v.push_back({2, 2});

    std::cout << (*it).front() << " " << (*(v.end()-1)).front() << std::endl;
    return 0;
}

However, it produces a segmentation fault at runtime :

0 1
Segmentation fault.

Why?