magento2 - Magento 2 webapi INR error While place order -

i got error while placing order in magento 2. order placed in magento 2 backend. got error this.

main.critical: exception: report id: webapi-56b84c8611046; message: notice: undefined index: inr in app/code/webkul/marketplace/observer/salesorderplaceafterobserver.php on line 303 in vendor/magento/framework/webapi/errorprocessor.php:194 stack trace: #0 vendor/magento/framework/webapi/errorprocessor.php(139): magento\framework\webapi\errorprocessor->_critical(object(exception)) #1 vendor/magento/module-webapi/controller/rest.php(163): magento\framework\webapi\errorprocessor->maskexception(object(exception)) #2 var/generation/magento/webapi/controller/rest/interceptor.php(24): magento\webapi\controller\rest->dispatch(object(magento\framework\app\request\http)) #3 vendor/magento/framework/app/http.php(115): magento\webapi\controller\rest\interceptor->dispatch(object(magento\framework\app\request\http)) #4 vendor/magento/framework/app/bootstrap.php(258): magento\framework\app\http->launch() #5 index.php(39): magento\framework\app\bootstrap->run(object(magento\framework\app\http)) 

kindly me .

it bug in webkul marketplace extension, should contact developer support.