By default the engine should be set to the latest LTS release, however, I'd suggest to make sure all components are updated to the latest version and try again. If the issue persists, I'd suggest to create a
Public Issue tracker and provide the error message, and this can be investigated further.
In regards to App engine Standard, more information can be found
here. There are certain limitations in terms of updates in comparison to Flex, however, it does support the latest stable release of Node.js.