diff --git a/includes/query/class-tmdo-post-query-router.php b/includes/query/class-tmdo-post-query-router.php
index 443505e..623585a 100644
--- a/includes/query/class-tmdo-post-query-router.php
+++ b/includes/query/class-tmdo-post-query-router.php
@@ -678,11 +678,17 @@ class TMDO_Post_Query_Router {
 	 */
 	private static function route_clause( array $clause, array $field ): ?array {
 		$compare = strtoupper( trim( (string) ( $clause['compare'] ?? '=' ) ) );
-		$type    = strtoupper( trim( (string) ( $clause['type'] ?? '' ) ) );
-		$type    = '' === $type ? 'CHAR' : $type;
-		$value   = $clause['value'] ?? '';
-		$kind    = $field['type'] ?? 'text';
-		$multi   = in_array( $compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ), true );
+		// Without 'value', WP_Meta_Query checks only that the key exists (it adds a
+		// value condition only when one is set): HivePress's featured-listing
+		// lookup, run on every search page, is array( 'key' => 'hp_featured' ).
+		if ( ! array_key_exists( 'value', $clause ) && ! in_array( $compare, array( 'EXISTS', 'NOT EXISTS' ), true ) ) {
+			$compare = 'EXISTS';
+		}
+		$type  = strtoupper( trim( (string) ( $clause['type'] ?? '' ) ) );
+		$type  = '' === $type ? 'CHAR' : $type;
+		$value = $clause['value'] ?? '';
+		$kind  = $field['type'] ?? 'text';
+		$multi = in_array( $compare, array( 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN' ), true );
 
 		if ( ! in_array( $compare, self::COMPARES, true ) || ( ! $multi && is_array( $value ) ) ) {
 			return null;
diff --git a/tests/integration/PostQueryRouterTest.php b/tests/integration/PostQueryRouterTest.php
index 2f82d5b..83f94ac 100644
--- a/tests/integration/PostQueryRouterTest.php
+++ b/tests/integration/PostQueryRouterTest.php
@@ -412,4 +412,28 @@ class PostQueryRouterTest extends TestCase {
 
 		$this->assertStringContainsString( "LIKE '%B1\\\\_1\\\\%%'", $router->posts_where( '', $query ) );
 	}
+
+	/**
+	 * A clause with no value tests only that the key exists (WP_Meta_Query adds
+	 * a value condition only when 'value' is set), so it routes as EXISTS.
+	 * HivePress's featured-listing lookup on every search page is one:
+	 * array( 'key' => 'hp_featured' ) — it kept the whole query native (2.4 PR-122).
+	 */
+	public function test_a_clause_without_a_value_routes_as_exists(): void {
+		$this->set_post_mode( 'aeav_only' );
+		$router = new WPDO_Post_Query_Router();
+		$query  = $this->make_query(
+			array(
+				'post_type'  => 'product',
+				'meta_query' => array(
+					array( 'key' => '_stock' ),
+					array( 'key' => '_price', 'value' => array( 10, 20 ), 'compare' => 'BETWEEN', 'type' => 'NUMERIC' ),
+				),
+			)
+		);
+		$router->pre_get_posts( $query );
+
+		$this->assertEmpty( $query->get( 'meta_query' ), 'both clauses routed' );
+		$this->assertStringContainsString( '`_stock` IS NOT NULL', $router->posts_where( '', $query ) );
+	}
 }