[Book1] Ch9 Rendering color wrong

[Penguin-SAMA]

I have encountered a strange issue.
When I use the following piece of code:

inline double random_double() {
    static std::uniform_real_distribution<double> distribution(0.0, 1.0);
    static std::mt19937 generator;
    return distribution(generator);
}

inline double random_double(double min, double max) {
    return min + (max - min) * random_double();
}

The output in image.ppm is like this:

However, if I modify the code to this:

inline double random_double() { return rand() / (RAND_MAX + 1.0); }

image.ppm changes to this:

I am not sure what is going wrong, and after a detailed review of the code, I couldn't find any issues.
How should I modify the program to address this?

[Penguin-SAMA]

update

i use the new code:

inline double random_double() {
    static std::random_device rd;
    static std::mt19937 generator(rd());
    static std::uniform_real_distribution<double> distribution(0.0, 1.0);
    return distribution(generator);
}

The output is true now

But I still don't know why this error occurs