symfony: Console: Running default command causes invalid hasAnArrayArgument state

Q	A
Bug report?	yes
Feature request?	no
BC Break report?	no
RFC?	no
Symfony version	3.4.2

Got an exception

When I run php my-script.php. Seems like a bug to me because no matter how I order the arguments the problem still occurs.

Expected:

Not enough arguments (missing: “invoice-id, customer”).

Actual:

Cannot add a required argument after an optional one.

Caused by Symfony\Component\Console\Input\InputDefinition::addArgument.

<?php


namespace Mite\Console;


use Mite\Mite;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;

class PdfCommand extends Command {
    protected static $defaultName = 'mite:pdf';

    protected function configure() {
        // $this->addOption( 'month', 'm', InputOption::VALUE_OPTIONAL, 'Month which shall be invoiced', date( 'm' ) );

        $this->addArgument( 'invoice-id', InputArgument::REQUIRED, 'ID of the invoice' );
        $this->addArgument( 'customer', InputArgument::REQUIRED, 'Name of the customer as stored in mite' );

        $this->addOption( 'month', 'm', InputOption::VALUE_OPTIONAL, 'Month which shall be invoiced', date( 'm' ) );
    }

    protected function execute( InputInterface $input, OutputInterface $output ) {

    }
}

app.php

<?php

require_once __DIR__ . '/../vendor/autoload.php';

$app = new \Symfony\Component\Console\Application( 'mite-pdf' );

$app->addCommands( [
	new \Mite\Console\PdfCommand(),
] );

$app->setDefaultCommand('mite:pdf');

$app->run();