Ok, problem solved!
Here is the code I had to add to make it work:
function custom_wpkses_post_tags( $tags, $context ) {
if ( 'acf' === $context ) {
$tags['input'] = array(
'type' => true,
'disabled' => true,
'checked' => true,
'style' => true,
'name' => true,
'value' => true,
);
}
return $tags;
}
add_filter( 'wp_kses_allowed_html', 'custom_wpkses_post_tags', 10, 2 );