file class-sitemaps-router.php

patch wp-content/plugins/wordpress/seo/inc/sitemaps/class-sitemaps-router.php

line 39

$dynamic_rewrites->add_rule( ‘sitemap_index.xml$’, ‘index.php?sitemap=1’, ‘top’ );

line 97

YoastSEO()->helpers->redirect->do_safe_redirect( home_url( ‘/sitemap_index.xml’ ), 301, ‘Yoast SEO’ );