Duplicate Button Appears While Theming Buttons

Hello,

I am developing a custom form in Drupal 8.1.9. I need to theme my submit button and decided to convert it to a . My code is as follows:

buildForm

        // Submit
        $form['actions']['submit'] = array(
            '#type' => 'submit',
            '#value' => t('Submit Form'),
            '#submit' => array('submitForm'),
        );

hook_form_alter

    if ( isset ($form['actions']) ) {
        foreach ($form['actions'] as $key => $value) {
            if ( in_array( $value['#type'], array('submit', 'button')) ) {
                $form['actions'][$key]['#theme'] = array('my_theme_button');
            }
        }
    }

hook_theme

        'hb_forms_button' => array (
            'render element' => 'values',
            'template' => 'input--button',
        ),

input–button.html.twig

{%
set classes = [
   'btn',
   'btn-block',
   'btn-info',
 ]
%}
<div class="form-group text-center">
	<div class="col-sm-12 controls">
		<button{{ attributes.addClass(classes) }}>{{ values['#value'] }}</button>
	</div>
</div>

The result is which I cannot show you is that my new stylized button appears but next to it is the another one that is generated by Drupal. Both have the same label. One is an where as the one is a . Any ideas would be great as I would hate to resort to using style to hide the former.

Thanks

Drupal version: 


Source: https://www.drupal.org/taxonomy/term/4/feed