Add Jetpack Markdown to an ACF Textarea field

acf-textarea-markdown.php

<?php

/**
 * Filter an ACF field to add Markdown support with Jetpack
 * 
 * @link https://www.advancedcustomfields.com/resources/acfload_value/
 */
add_filter('acf/load_value/type=textarea', function ($content) {
    return wpautop(
        WPCom_Markdown::get_instance()->transform($content)
    );
});