Eigen Map<> possible bug

MatrixSequence.h

#include <vector>
#include <Eigen/Dense>

class MatrixSequence
{
public:
    MatrixSequence() {
        data_.resize(1);
        data_[0]=0;
    }

    Eigen::Map<Eigen::MatrixXd> matrix_compile() {
        auto* beginning = &data_.at(0);       //double*
        Map<Matrix> out(beginning, 1, 0);
        return out;
    }


    Eigen::Map<Eigen::MatrixXd> matrix_dont_compile() const {
        auto* beginning = &data_.at(0);       // const double*
        Map<Matrix> out(beginning, 1, 0);
        return out;
    }

private:
    std::vector<double> data_;
};