Inconsistent table encoding?

I've got a database that I've developed over time using Phinx. One issue I discovered along the way was that the tables were formatted using the latin1 character set and cp1252 West European encoding. So while consolidating Phinx migrations, I started explicitly setting the encoding as seen below:

<?php
declare(strict_types=1);

use Migrations\AbstractMigration;

class CreateCarts extends AbstractMigration
{
    /**
     * Change Method.
     *
     * More information on this method is available here:
     * https://book.cakephp.org/phinx/0/en/migrations.html#the-change-method
     * @return void
     */
    public function change()
    {
        $table = $this->table('carts', [
            'encoding' => 'utf8mb4',
            'collation' => 'utf8mb4_unicode_ci',
            ])
            ->addColumn('user_id', 'integer', [
                'default' => null,
                'null' => false,
                ])
            ->addColumn('cart_status', 'string', [
                'default' => 'active',
                'null' => false,
                ])
            ->addColumn('created', 'datetime', [
                'default' => null,
                'null' => false,
            ])
            ->addColumn('modified', 'datetime', [
                'default' => null,
                'null' => false,
            ])
            ->addColumn('cart_total', 'float', [
                'default' => null,
            ]);
        $table->create();
    }
}

However, when reviewing the tables, I discovered that not all of the tables are properly encoded despite explicitly being set in the options array shown here? Some do indeed take the UTF-8 multibyte encoding and some do not.

There are no other, altering migrations any longer because I consolidated them: only one migration creates a database and it does not get altered futher in the migration process. Any idea why this would be?

Start with the CreateCarts migration and its change() method, especially the table() encoding and collation options. Compare the resulting tables with the migration definitions and determine why some do not use utf8mb4. Done means the cause is reproducible and the expected encoding behavior is clearly established.