Error when enabling 'web' middleware

[mooxnl]

I got everything working, except when I enable the 'web' middleware (to support sessions) I get this error: Attempt to read property "only" on string

See:

Here, the variable $middleware contains 'web'.

This is my config/wire-extender.php:

<?php

return [
    /*
     * Define middlewares for the `livewire/embed` route.
     * Add the 'web' middleware if you want to support sessions.
     */
    'middlewares' => [
        'web',
    ],
];

Any idea what's wrong?