Laravel 5.7雄辩的记忆问题

I'm running the latest version of Laravel (v5.7.19), and have a little issue. I have a seeder than is running loop inside another one, and doing a simple query.

foreach ($tests as $test) {
    foreach ($anothers as $another) {
        Test::where('column', 123);
    }
}

This runs without any issues. I'm using memory_get_usage for the memory check.
As soon as I change the line to Test::where('column', 123)->first(); I run into huge memory problems. Does anyone have any ideas around this one?