When a console command defines one or more input arguments that have the same name(s) as defined OutputFormatterStyles, the HelpCommand output strips those arguments from the Usage section of the output and applies that style to the content that follows.

This is occurring because in Symfony\Component\Console\Input\InputDefinition::getSynopsis() (https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Console/Input/InputDefinition.php#L398) those argument names are wrapped in < and > and so the argument is treated as the opening tag of a style wrapper:

        foreach ($this->getArguments() as $argument) {
            $element = '<'.$argument->getName().'>';
[...]
        }

An example command that defines the argument names "info", "comment", and "foo" as follows:

    protected function configure() {
        $this->addArgument('info', InputArgument::REQUIRED, 'The first argument.');
        $this->addArgument('comment', InputArgument::OPTIONAL, 'The second argument.');
        $this->addArgument('foo', InputArgument::OPTIONAL, 'The third argument.');
    }

... would appear as follows when running help for that command. Note that the yellow foreground color of the default comment style is being applied to the following text in the output:

... when the expected output would be more like: