diff --git a/src/wp-includes/class-wp-theme-json-resolver.php b/src/wp-includes/class-wp-theme-json-resolver.php
index 993543a55b2b7..18b997561cf05 100644
--- a/src/wp-includes/class-wp-theme-json-resolver.php
+++ b/src/wp-includes/class-wp-theme-json-resolver.php
@@ -548,8 +548,7 @@ public static function get_merged_data( $origin = 'custom' ) {
 			_deprecated_argument( __FUNCTION__, '5.9.0' );
 		}
 
-		$result = new WP_Theme_JSON();
-		$result->merge( static::get_core_data() );
+		$result = static::get_core_data();
 		$result->merge( static::get_block_data() );
 		$result->merge( static::get_theme_data() );