Fix fatal error for the Multibanco email instructions method (#4349)

* Fix fatal error for the Multibanco email instructions method

* Changelog and readme entries

Author: wjrosa

changelog.txt

@@ -6,6 +6,7 @@
 * Tweak - Track charge completed via webhooks in order notes
 * Fix - Ensure that we migrate payment_request_button_size=medium on upgrade
 * Fix - Show correct price in express checkout for zero decimal currencies
+* Fix - Fixes a possible fatal error with Multibanco purchases when generating the email instructions.
 
 = 9.5.2 - 2025-05-22 =
 * Add - Implement custom database cache for persistent caching with in-memory optimization.

includes/payment-methods/class-wc-gateway-stripe-multibanco.php

@@ -225,6 +225,10 @@ public function thankyou_page( $order_id ) {
 	 * @param bool     $plain_text
 	 */
 	public function email_instructions( $order, $sent_to_admin, $plain_text = false ) {
+		if ( ! is_a( $order, 'WC_Order' ) ) {
+			return;
+		}
+
 		$order_id = $order->get_id();
 
 		$payment_method = $order->get_payment_method();

readme.txt

@@ -117,5 +117,6 @@ If you get stuck, you can ask for help in the [Plugin Forum](https://wordpress.o
 * Tweak - Track charge completed via webhooks in order notes
 * Fix - Ensure that we migrate payment_request_button_size=medium on upgrade
 * Fix - Show correct price in express checkout for zero decimal currencies
+* Fix - Fixes a possible fatal error with Multibanco purchases when generating the email instructions.
 
 [See changelog for full details across versions](https://raw.githubusercontent.com/woocommerce/woocommerce-gateway-stripe/trunk/changelog.txt).