Got no race condition in ticks_race.js, but got in request_eace.js

request_race.js

/* eslint-disable strict */

const http = require('http')
const https = require('https')
const assert = require('assert')

const port = 9000

let global_start = null;

// function sleep(ms) {
//   return new Promise(resolve => {
//     setTimeout(resolve, ms)
//   })
// }

function requestPromiseToAsync(options) {
  return new Promise((resolve) => {
    https.get(options, function (resp) {
      resp.on('data', function (data) {
        Response = data;
        resolve(resp.statusCode);
      });
    });
  });
}

const server = http.createServer(async function (request, response) {
  let start = Date.now();
  global_start = start;
  console.log(`starting: ${start}`)
  for (i = 0; i < 10000; i++) {
    console.log(`starting request ${i + 1} for ${start}`)
    let resultStatus = await requestPromiseToAsync('https://recaptcha.google.com/recaptcha/api/siteverify')
    // await sleep(2500)
    console.log(`completed request ${i + 1} for ${start}, global_start was ${global_start}`)
    assert(resultStatus == 200);
    if (global_start != start) {
      console.log(`Detected race condition, start: ${start}, global_start: ${global_start}`)
    }
  }
  end = Date.now();
  response.end(`${start}`);
});

server.listen(port);

let count = 0;
let timer = setInterval(() => {
  count += 1;
  if (count == 50)
    clearInterval(timer);
  console.log('starting request');
  http.get(`http://localhost:${port}`, function (res) {
    res.on('data', function (chunk) {
      console.log('finished request: ' + chunk);
    });
  })
}, 50)

ticks_race.js

/* eslint-disable strict */

const http = require('http')
const port = 9000

let global_start = null;

function f1() {
    let start = Date.now()
    global_start = start
    console.log(`starting: ${start}`)
    for (i = 0; i < 100000; i++) {
        for (j = 0; j < 10000; j++) {
            if (global_start != start) {
                console.log(`Detected race condition, start: ${start}, global_start: ${global_start}`)
            }
        }
    }
    end = Date.now();
    return `${start}`;
}

const server = http.createServer(function (request, response) {
    response.end(f1());
});

server.listen(port);

setInterval(() => {
    console.log('starting request');
    http.get(`http://localhost:${port}`, function (res) {
        res.on('data', function (chunk) {
            console.log('finished request: ' + chunk);
        });
    })
}, 1)