Stylesheet specified in register_block_style is not enqueued on front-end

I am using this bit of code to register a custom button style, but it doesn’t seem to work on the front-end.

add_action('init', function() {

	wp_register_style(
		'cms-button',
		get_template_directory_uri() . '/assets/css/button-custom.css',
		array(),
		filemtime( get_template_directory() . '/assets/css/button-custom.css' )
	);

	register_block_style('core/button', [
		'name' => 'custom',
		'label' => __('Custom', 'cms'),
		'style_handle' => 'cms-button'
	]);

});

In admin:
– The style option appears in admin UI
– Custom class is added to the markup
– CSS is enqueued

On the front-end:
– Custom class is added to the markup
– CSS is NOT enqueued, neither as a separate stylesheet nor inline

Is this expected behavior? I was under the impression that the stylesheet will be enqueued for both whenever button block is used.

Any advice would be greatly appreciated.