MC-42639: Payment error after session time out

Author: victor-v-rad

app/code/Magento/Persistent/Model/QuoteManager.php

@@ -182,6 +182,7 @@ public function convertCustomerCartToGuest()
             $quote->getAddressesCollection()->walk('setCustomerId', ['customerId' => null]);
             $quote->getAddressesCollection()->walk('setEmail', ['email' => null]);
             $quote->collectTotals();
+            $quote->getCustomer()->setId(null);
             $this->persistentSession->getSession()->removePersistentCookie();
             $this->persistentSession->setSession(null);
             $this->quoteRepository->save($quote);

app/code/Magento/Persistent/Test/Unit/Model/QuoteManagerTest.php

@@ -134,6 +134,7 @@ protected function setUp(): void
                 'setExtensionAttributes',
                 '__wakeup',
                 'setCustomer',
+                'getCustomer'
             ])
             ->disableOriginalConstructor()
             ->getMock();
@@ -343,6 +344,13 @@ public function testConvertCustomerCartToGuest()
             ->method('setIsPersistent')->with(false)->willReturn($this->quoteMock);
         $this->quoteMock->expects($this->exactly(3))
             ->method('getAddressesCollection')->willReturn($this->abstractCollectionMock);
+        $customerMock = $this->createMock(CustomerInterface::class);
+        $customerMock->expects($this->once())
+            ->method('setId')
+            ->with(null)
+            ->willReturnSelf();
+        $this->quoteMock->expects($this->once())
+            ->method('getCustomer')->willReturn($customerMock);
         $this->abstractCollectionMock->expects($this->exactly(3))->method('walk')->with(
             $this->logicalOr(
                 $this->equalTo('setCustomerAddressId'),