diff --git a/src/wp-includes/nav-menu.php b/src/wp-includes/nav-menu.php
index a063835fda341..d808c4e212d39 100644
--- a/src/wp-includes/nav-menu.php
+++ b/src/wp-includes/nav-menu.php
@@ -491,17 +491,25 @@ function wp_update_nav_menu_item( $menu_id = 0, $menu_item_db_id = 0, $menu_item
 		$args['menu-item-url'] = '';
 
 		$original_title = '';
+
 		if ( 'taxonomy' === $args['menu-item-type'] ) {
-			$original_parent = get_term_field( 'parent', $args['menu-item-object-id'], $args['menu-item-object'], 'raw' );
-			$original_title  = get_term_field( 'name', $args['menu-item-object-id'], $args['menu-item-object'], 'raw' );
-		} elseif ( 'post_type' === $args['menu-item-type'] ) {
+			$original_object = get_term( $args['menu-item-object-id'], $args['menu-item-object'] );
 
+			if ( $original_object instanceof WP_Term ) {
+				$original_parent = get_term_field( 'parent', $args['menu-item-object-id'], $args['menu-item-object'], 'raw' );
+				$original_title  = get_term_field( 'name', $args['menu-item-object-id'], $args['menu-item-object'], 'raw' );
+			}
+		} elseif ( 'post_type' === $args['menu-item-type'] ) {
 			$original_object = get_post( $args['menu-item-object-id'] );
-			$original_parent = (int) $original_object->post_parent;
-			$original_title  = $original_object->post_title;
+
+			if ( $original_object instanceof WP_Post ) {
+				$original_parent = (int) $original_object->post_parent;
+				$original_title  = $original_object->post_title;
+			}
 		} elseif ( 'post_type_archive' === $args['menu-item-type'] ) {
 			$original_object = get_post_type_object( $args['menu-item-object'] );
-			if ( $original_object ) {
+
+			if ( $original_object instanceof WP_Post_Type ) {
 				$original_title = $original_object->labels->archives;
 			}
 		}
diff --git a/tests/phpunit/tests/post/nav-menu.php b/tests/phpunit/tests/post/nav-menu.php
index 7a320f9f8d628..d4ece1ff1776c 100644
--- a/tests/phpunit/tests/post/nav-menu.php
+++ b/tests/phpunit/tests/post/nav-menu.php
@@ -1208,6 +1208,35 @@ public function test_wp_update_nav_menu_item_with_special_characters_in_category
 		$this->assertEmpty( $category_item->post_title );
 	}
 
+	/**
+	 * Tests `wp_update_nav_menu_item()` with a non-existing taxonomy.
+	 *
+	 * When inserting a term from a non-existing taxonomy as a nav item,
+	 * the `post_title` property should be empty, and the function
+	 * should not throw a fatal error for `wp_specialchars_decode()`.
+	 *
+	 * @ticket 61799
+	 */
+	public function test_wp_update_nav_menu_item_with_invalid_taxonomy() {
+		register_taxonomy( 'invalid', 'post' );
+		$term = self::factory()->term->create_and_get( array( 'taxonomy' => 'invalid' ) );
+		unregister_taxonomy( 'invalid' );
+
+		$menu_item_id = wp_update_nav_menu_item(
+			$this->menu_id,
+			0,
+			array(
+				'menu-item-type'      => 'taxonomy',
+				'menu-item-object'    => 'invalid',
+				'menu-item-object-id' => $term->term_id,
+				'menu-item-status'    => 'publish',
+			)
+		);
+
+		$menu_item = get_post( $menu_item_id );
+		$this->assertEmpty( $menu_item->post_title );
+	}
+
 	/**
 	 * Test passed post_date/post_date_gmt.
 	 *