// trailing /index.php
$redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);
// trailing /index.php
$redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);