Node.js 'socket hang up' and keep-alive - node.js

Question

I have a very strange error happening.
I am running Node.js version 8.0.0 on Mac OS X Sierra.
I create a very simple http server that basically returns 'ok' to any request after 8 seconds in this example.
I then use the 'request' package to make a request to my http server every 9 seconds, and use the parameter 'forever' to keep the http session alive.
One request out of two works perfectly fine while the other out of two returns a 'socket hang up' error.
Here is the very simple code to reproduce the issue:
const http = require('http');
const request = require('request');
const port = 3000;
const server = http.createServer((req, res) => {
console.log('request');
setTimeout(() => {
res.end('ok');
}, 8000);
});
server.listen(port);
setInterval(() => {
request(`http://localhost:${port}/`, {forever: true}, (error, response, body) => {
if (error) return console.log('error', error);
console.log('done', body);
});
}, 9000);
When I run this code I get the following output on my Macbook Pro :
request
done ok
request
error { Error: socket hang up
at createHangUpError (_http_client.js:343:15)
at Socket.socketOnEnd (_http_client.js:435:23)
at emitNone (events.js:110:20)
at Socket.emit (events.js:207:7)
at endReadableNT (_stream_readable.js:1045:12)
at _combinedTickCallback (internal/process/next_tick.js:102:11)
at process._tickCallback (internal/process/next_tick.js:161:9) code: 'ECONNRESET' }
request
done ok
request
error { Error: socket hang up
at createHangUpError (_http_client.js:343:15)
at Socket.socketOnEnd (_http_client.js:435:23)
at emitNone (events.js:110:20)
at Socket.emit (events.js:207:7)
at endReadableNT (_stream_readable.js:1045:12)
at _combinedTickCallback (internal/process/next_tick.js:102:11)
at process._tickCallback (internal/process/next_tick.js:161:9) code: 'ECONNRESET' }
request
done ok
request
error { Error: socket hang up
at createHangUpError (_http_client.js:343:15)
at Socket.socketOnEnd (_http_client.js:435:23)
at emitNone (events.js:110:20)
at Socket.emit (events.js:207:7)
at endReadableNT (_stream_readable.js:1045:12)
at _combinedTickCallback (internal/process/next_tick.js:102:11)
at process._tickCallback (internal/process/next_tick.js:161:9) code: 'ECONNRESET' }
So I get an 'socket hang up' error exactly every other request.
It seems that the error does not seem to appear on an Ubuntu VPS though.
Any ideas as to why this issue is happening ?