Undefined index 'charge_permission_id'

Async Error log was full of these.  

amazonAsyncIpnLogger.ERROR: Exception: Notice: Undefined index: charge_permission_id in /var/www/shop/prod/vendor/amzn/amazon-pay-magento-2-module/Model/AsyncManagement/Charge.php on line 213 in /var/www/shop/prod/vendor/magento/framework/App/ErrorHandler.php:61
Stack trace:
#0 /var/www/shop/prod/vendor/amzn/amazon-pay-magento-2-module/Model/AsyncManagement/Charge.php(213): Magento\Framework\App\ErrorHandler->handler()
#1 /var/www/shop/prod/vendor/amzn/amazon-pay-magento-2-module/Model/AsyncManagement/Charge.php(167): Amazon\Pay\Model\AsyncManagement\Charge->decline()
#2 /var/www/shop/prod/vendor/amzn/amazon-pay-magento-2-module/Model/AsyncUpdater.php(79): Amazon\Pay\Model\AsyncManagement\Charge->processStateChange()
#3 /var/www/shop/prod/vendor/amzn/amazon-pay-magento-2-module/Cron/ProcessAsync.php(71): Amazon\Pay\Model\AsyncUpdater->processPending()
#4 [internal function]: Amazon\Pay\Cron\ProcessAsync->execute()
#5 /var/www/shop/prod/vendor/magento/module-cron/Observer/ProcessCronQueueObserver.php(368): call_user_func_array()
#6 /var/www/shop/prod/vendor/magento/module-cron/Observer/ProcessCronQueueObserver.php(879): Magento\Cron\Observer\ProcessCronQueueObserver->_runJob()
#7 /var/www/shop/prod/vendor/magento/module-cron/Observer/ProcessCronQueueObserver.php(840): Magento\Cron\Observer\ProcessCronQueueObserver->tryRunJob()
#8 /var/www/shop/prod/vendor/magento/module-cron/Observer/ProcessCronQueueObserver.php(280): Magento\Cron\Observer\ProcessCronQueueObserver->processPendingJobs()
#9 /var/www/shop/prod/vendor/magento/framework/Event/Invoker/InvokerDefault.php(88): Magento\Cron\Observer\ProcessCronQueueObserver->execute()
#10 /var/www/shop/prod/vendor/magento/framework/Event/Invoker/InvokerDefault.php(74): Magento\Framework\Event\Invoker\InvokerDefault->_callObserverMethod()
#11 /var/www/shop/prod/vendor/magento/framework/Event/Manager.php(66): Magento\Framework\Event\Invoker\InvokerDefault->dispatch()
#12 /var/www/shop/prod/generated/code/Magento/Framework/Event/Manager/Proxy.php(95): Magento\Framework\Event\Manager->dispatch()
#13 /var/www/shop/prod/vendor/magento/framework/App/Cron.php(86): Magento\Framework\Event\Manager\Proxy->dispatch()
#14 /var/www/shop/prod/vendor/magento/module-cron/Console/Command/CronCommand.php(117): Magento\Framework\App\Cron->launch()
#15 /var/www/shop/prod/vendor/symfony/console/Command/Command.php(255): Magento\Cron\Console\Command\CronCommand->execute()
#16 /var/www/shop/prod/vendor/magento/framework/Interception/Interceptor.php(58): Symfony\Component\Console\Command\Command->run()
#17 /var/www/shop/prod/vendor/magento/framework/Interception/Interceptor.php(138): Magento\Cron\Console\Command\CronCommand\Interceptor->___callParent()
#18 /var/www/shop/prod/vendor/magento/framework/Interception/Interceptor.php(153): Magento\Cron\Console\Command\CronCommand\Interceptor->Magento\Framework\Interception\{closure}()
#19 /var/www/shop/prod/generated/code/Magento/Cron/Console/Command/CronCommand/Interceptor.php(77): Magento\Cron\Console\Command\CronCommand\Interceptor->___callPlugins()
#20 /var/www/shop/prod/vendor/symfony/console/Application.php(1009): Magento\Cron\Console\Command\CronCommand\Interceptor->run()
#21 /var/www/shop/prod/vendor/symfony/console/Application.php(273): Symfony\Component\Console\Application->doRunCommand()
#22 /var/www/shop/prod/vendor/magento/framework/Console/Cli.php(115): Symfony\Component\Console\Application->doRun()
#23 /var/www/shop/prod/vendor/symfony/console/Application.php(149): Magento\Framework\Console\Cli->doRun()
#24 /var/www/shop/prod/bin/magento(23): Symfony\Component\Console\Application->run()
#25 {main} [] []

Model/AsyncManagement/Charge.php

@@ -210,7 +210,7 @@ public function decline($order, $chargeId, $detail)
             $this->closeLastTransaction($order);
             $this->amazonAdapter->closeChargePermission(
                 $order->getStoreId(),
-                $order->getPayment()->getAdditionalInformation()['charge_permission_id'],
+                array_key_exists('charge_permission_id', $order->getPayment()->getAdditionalInformation()) ? $order->getPayment()->getAdditionalInformation()['charge_permission_id'] : "",
                 'Canceled due to capture declined.',
                 true
             );