The documentation section Error-handling guidelines contains the sentences

Trying to reproduce this behaviour with Example project brings unexpected results. The way I had tried:

1. Setup database
2. Start the example server
3. Open http://127.0.0.1:8000 in the Chrome
4. Open DevTools with network and console tabs
5. Click on api WebSocket request and there on Messages tab. Check that auth/signin request was successful with the status logged.
6. Write in console await api.example.customException();
7. The result {message: "Custom ecxeption", code: 12345} despite documentation says that unknown error code will generate: "Internal Server Error" with "code":500.
8. Change error code in the file application/api/example/customException.js to 404. Save and check that update has been reloaded by server.
9. Call again in console await api.example.customException();
10. The result {message: "Custom ecxeption", code: 404} instead of automatic replacement of the message with "Not found" as being told at the documentation.
11. The same behaviour with public endpoint.

What is the desired latest behaviour: that mentioned in documentation OR that actually works in Example?