the array for your repeater should look like this
$value = array(
// nested for each row
array(
// field key => value pairs
'field_59606dc9525dc' => 'value for row 1'
),
array(
// field key => value pairs
'field_59606dc9525dc' => 'value for row 2'
),
);
I think that this will do it
foreach ($wpbb_xml_params->features->children() as $second_gen) {
$feature_value = (string)$second_gen;
$value[] = array( 'field_59606dc9525dc' => $feature_value );
}
update_field( 'field_59606db8525db', $value, $wpbb_job_post_id );