diff --git a/tests/includes/transformer/class-test-post.php b/tests/includes/transformer/class-test-post.php
index a6a07202c..803d86f5c 100644
--- a/tests/includes/transformer/class-test-post.php
+++ b/tests/includes/transformer/class-test-post.php
@@ -370,6 +370,16 @@ public function test_block_attachments_with_fallback() {
 			)
 		);
 
+		// For WP versions 6.1 and prior, we only look for attached images.
+		if ( ! class_exists( 'WP_HTML_Tag_Processor' ) ) {
+			wp_update_post(
+				array(
+					'ID'          => $attachment_id,
+					'post_parent' => $post_id,
+				)
+			);
+		}
+
 		$object = Post::transform( get_post( $post_id ) )->to_object();
 
 		$this->assertEquals(