diff --git a/bu-navigation.php b/bu-navigation.php
index 2076bc7..7c632cc 100644
--- a/bu-navigation.php
+++ b/bu-navigation.php
@@ -5,7 +5,7 @@
  * Author: Boston University (IS&T)
  * Author URI: http://sites.bu.edu/web/
  * Description: Provides alternative navigation elements designed for blogs with large page counts
- * Version: 1.3.6
+ * Version: 1.3.7
  * Text Domain: bu-navigation
  * Domain Path: /languages
  * License: GPL2+
@@ -94,7 +94,7 @@ class BU_Navigation_Plugin {
 	 *
 	 * @var string
 	 */
-	const VERSION = '1.3.6';
+	const VERSION = '1.3.7';
 
 	/**
 	 * Plugin class constructor.
diff --git a/composer-includes/bu-navigation-core-widget/src/data-get-urls.php b/composer-includes/bu-navigation-core-widget/src/data-get-urls.php
index 5ced43b..d8fbfdc 100644
--- a/composer-includes/bu-navigation-core-widget/src/data-get-urls.php
+++ b/composer-includes/bu-navigation-core-widget/src/data-get-urls.php
@@ -218,6 +218,35 @@ function get_page_uri( $page, $ancestors ) {
  */
 function get_page_uri_ancestors( $post ) {
 
+	// Try the cache first, mirroring load_sections(). This call resolves a post's
+	// ancestor chain via load_sections() + the uncached get_nav_posts() query, and
+	// runs once per missing-ancestor chain on every front-end render. Without a
+	// persistent cache it re-runs the raw posts query on each request, which is the
+	// dominant source of wp_posts read amplification during crawls.
+	//
+	// The key is version-stamped on the core posts 'last_changed' value (bumped by
+	// clean_post_cache() on any post edit) and site-scoped. The 'bu-navigation' group
+	// is Redis-backed (persistent) in production. Freshness is fully handled by the
+	// last_changed stamp; the TTL is only a self-healing backstop for the rare case an
+	// edit bypasses clean_post_cache() (e.g. a direct $wpdb write or import). Unlike
+	// load_sections() (keyed on post types, so a few keys per site), this cache is keyed
+	// per post, so a short TTL is used to keep orphaned key generations -- one per
+	// last_changed bump -- from accumulating in Redis.
+	$last_changed = wp_cache_get( 'last_changed', 'posts' );
+	if ( ! $last_changed ) {
+		$last_changed = microtime();
+		wp_cache_set( 'last_changed', $last_changed, 'posts' );
+	}
+
+	$cache_key = 'page_uri_ancestors:' . get_current_blog_id() . ':' . md5( $post->ID . ':' . $post->post_type . ":$last_changed" );
+	$cached    = wp_cache_get( $cache_key, 'bu-navigation' );
+
+	// Use a strict check against false so that an empty-ancestors result (a top-level
+	// post with no ancestors) is still served from cache rather than recomputed.
+	if ( false !== $cached ) {
+		return $cached;
+	}
+
 	$ancestors    = array();
 	$all_sections = load_sections( $post->post_type );
 
@@ -246,6 +275,8 @@ function get_page_uri_ancestors( $post ) {
 		}
 	}
 
+	wp_cache_set( $cache_key, $ancestors, 'bu-navigation', HOUR_IN_SECONDS );
+
 	return $ancestors;
 }
 
diff --git a/readme.md b/readme.md
index f22286d..6db5697 100644
--- a/readme.md
+++ b/readme.md
@@ -4,7 +4,7 @@
 **Tags:** navigation, hierarchical, post type, boston university, bu
 **Requires at least:** 3.1
 **Tested up to:** 5.7
-**Stable tag:** 1.3.6
+**Stable tag:** 1.3.7
 **License:** GPLv2 or later
 **License URI:** http://www.gnu.org/licenses/gpl-2.0.html
 
@@ -115,6 +115,16 @@ Please see this page for the details:
 
 ## Changelog
 
+### 1.3.7
+
+* Makes the per-post ancestor lookup (`get_page_uri_ancestors`) persistent, mirroring the
+  1.3.6 `load_sections` change. This call resolves a post's ancestor chain when building
+  permalinks and ran an uncached posts query once per missing-ancestor chain on nearly every
+  front-end render — the dominant source of `wp_posts` read amplification during crawls.
+  Results are now cached in the site-scoped, version-stamped `bu-navigation` cache (invalidated
+  on any post edit, with a short TTL backstop), so permalinks render identically while the
+  underlying query is reused across requests.
+
 ### 1.3.6
 
 * Makes the navigation tree section cache (`load_sections`) persistent instead of
diff --git a/readme.txt b/readme.txt
index f75743c..c798e35 100644
--- a/readme.txt
+++ b/readme.txt
@@ -3,7 +3,7 @@ Contributors: ntk, mgburns, gcorne, jtwiest, awbauer, inderpreet99
 Tags: navigation, hierarchical, post type, boston university, bu
 Requires at least: 3.1
 Tested up to: 5.7
-Stable tag: 1.3.6
+Stable tag: 1.3.7
 License: GPLv2 or later
 License URI: http://www.gnu.org/licenses/gpl-2.0.html
 
@@ -79,6 +79,10 @@ Please see this page for the details:
 
 == Changelog ==
 
+= 1.3.7 =
+
+* Makes the per-post ancestor lookup (`get_page_uri_ancestors`) persistent, mirroring the 1.3.6 `load_sections` change. This call resolves a post's ancestor chain when building permalinks and ran an uncached posts query once per missing-ancestor chain on nearly every front-end render — the dominant source of `wp_posts` read amplification during crawls. Results are now cached in the site-scoped, version-stamped `bu-navigation` cache (invalidated on any post edit, with a short TTL backstop), so permalinks render identically while the underlying query is reused across requests.
+
 = 1.3.6 =
 
 * Makes the navigation tree section cache (`load_sections`) persistent instead of non-persistent, so the page-hierarchy `GROUP_CONCAT` query is reused across requests rather than re-run on nearly every front-end render. The cache key is site-scoped and version-stamped on the core posts cache, with a one-day TTL backstop; publication status, ordering, and navigation meta continue to be applied on the uncached posts query, so navigation output is unchanged.