Notice: Array to string conversion when using order rest API

[fxdegroot]

Preconditions

Magento EE 2.1.2 / Magento CE 2.1.2

Steps to reproduce

1. Make an order using PayPal Express as a payment method and then pay by entering credit card information within Paypal
2. Try to access this particular order via Magento REST api : /rest/V1/orders

Expected result

1. The API returns a JSON response of corresponding order

Actual result

1. You get the following error : Notice: Array to string conversion in vendor/magento/framework/Reflection/TypeCaster.php on line 34

PR : #8311

[YevSent]

Hi, @fxdegroot, thanks for reporting.

Do you have payment with enabled Vault feature?

[YevSent]

We are closing this issue because it hasn’t been updated in more than two weeks.

If you still can reproduce the issue, please, be free to reopen it.

[eharvest]

I'm trying to integrate Magento 2.1 with a third party accounting/inventory/pos software and I'm getting the same error, here is the whole error message:

{"message":"Notice: Array to string conversion in \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/Reflection\/TypeCaster.php on line 34","trace":"
#0 \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/Reflection\/TypeCaster.php(34): Magento\\Framework\\App\\ErrorHandler->handler(8, 'Array to string...', '\/var\/www\/live\/p...', 34, Array)\n
#1 \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/Reflection\/DataObjectProcessor.php(115): Magento\\Framework\\Reflection\\TypeCaster->castValueToType(Array, 'string')\n
#2 \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/Reflection\/DataObjectProcessor.php(107): Magento\\Framework\\Reflection\\DataObjectProcessor->buildOutputDataArray(Object(Magento\\Sales\\Model\\Order\\Payment\\Interceptor), '\\\\Magento\\\\Sales\\\\...')\n
#3 \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/Reflection\/DataObjectProcessor.php(113): Magento\\Framework\\Reflection\\DataObjectProcessor->buildOutputDataArray(Object(Magento\\Sales\\Model\\Order), '\\\\Magento\\\\Sales\\\\...')\n
#4 \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/Webapi\/ServiceOutputProcessor.php(107): Magento\\Framework\\Reflection\\DataObjectProcessor->buildOutputDataArray(Object(Magento\\Sales\\Model\\ResourceModel\\Order\\Collection), '\\\\Magento\\\\Sales\\\\...')\n
#5 \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/Webapi\/ServiceOutputProcessor.php(59): Magento\\Framework\\Webapi\\ServiceOutputProcessor->convertValue(Object(Magento\\Sales\\Model\\ResourceModel\\Order\\Collection), '\\\\Magento\\\\Sales\\\\...')\n
#6 \/var\/www\/live\/public_html\/magento2\/app\/code\/Magento\/Webapi\/Controller\/Rest.php(308): Magento\\Framework\\Webapi\\ServiceOutputProcessor->process(Object(Magento\\Sales\\Model\\ResourceModel\\Order\\Collection), 'Magento\\\\Sales\\\\A...', 'getList')\n
#7 \/var\/www\/live\/public_html\/magento2\/app\/code\/Magento\/Webapi\/Controller\/Rest.php(216): Magento\\Webapi\\Controller\\Rest->processApiRequest()\n
#8 \/var\/www\/live\/public_html\/magento2\/var\/generation\/Magento\/Webapi\/Controller\/Rest\/Interceptor.php(37): Magento\\Webapi\\Controller\\Rest->dispatch(Object(Magento\\Framework\\App\\Request\\Http))\n
#9 \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/App\/Http.php(135): Magento\\Webapi\\Controller\\Rest\\Interceptor->dispatch(Object(Magento\\Framework\\App\\Request\\Http))\n
#10 \/var\/www\/live\/public_html\/magento2\/lib\/internal\/Magento\/Framework\/App\/Bootstrap.php(258): Magento\\Framework\\App\\Http->launch()\n
#11 \/var\/www\/live\/public_html\/magento2\/pub\/index.php(37): Magento\\Framework\\App\\Bootstrap->run(Object(Magento\\Framework\\App\\Http))\n
#12 {main}"}

We were able to sync products but not orders. Is this a bug? Cheers.