functions.php

<?php
//
//	CUSTOM FILTER TO ADD COMMA AFTER TAXONOMY OUTPUT FOR FIELD EDITOR
//
//

add_filter( 'field_editor_output_no_wrap_after', 'mysite_check_if_need_to_output_csv', 10, 6 );

function mysite_check_if_need_to_output_csv( $separator, $field_slug, $job_id, $field_values, $args, $single_value ){

	// ADD ANY ADDITIONAL META KEYS TO USE WITH COMMAS BELOW
	$csv_meta_keys = array( 'job_skill', 'qualification_tag' );
	
	// If meta key is not one of our meta keys from above, return the default separator
	if( ! in_array( $field_slug, $csv_meta_keys ) ) return $separator;

	$last_value = end( array_values($field_values) );
	
	if( ! empty( $single_value ) && $last_value !== $single_value ) {
		return ', ';
	} else {
		return '';
	}

}