bug.php

<?php
require 'vendor/autoload.php';
$connection = new PDO(getenv('MYSQL'));
$looper = function () use ($connection) {
    foreach ([1, 2, 3] as $number) {
        yield $connection->query('select * from categories');
    }
};
$list = (new \Cake\Collection\Collection($looper()))->map(function($r) { return $r; });
iterator_to_array($list, false);

test.sh

#!/bin/bash

composer require cakephp/collection=dev-master
php bug.php