I'm missing something in how to fix this ...

myBug.js

import { just, iterate } from 'most';

const inputString = 'initial';

just(inputString)
  .tap(x => console.log(`my initial string ${x}`))
  .chain(() => iterate(x => x + 1, 1))
  .tap(x => console.log(`generated chapter url ${x}`))
  .take(4) // If I remove this line, I get the requests starting, but then I get stuck in an infinite loop of generated chapters url
  .map(x => {
    return just(x)
      .tap(x => console.log(`starting request for chapter ${x}`))
      .delay(1000)
      .tap(x => console.log(`received chapter ${x}`));
  })
  .mergeConcurrently(2)
  .subscribe({
    next: () => {},
    error: err => console.error(err),
    complete: () => {},
  });

/* This is the output
$ node lib/myBug.js
my initial string initial
generated chapter url 1
starting request for chapter 1
generated chapter url 2
starting request for chapter 2
generated chapter url 3
generated chapter url 4
received chapter 1
received chapter 2
starting request for chapter 3
starting request for chapter 4
received chapter 3
received chapter 4

Why isn't it 

$ node lib/myBug.js
my initial string initial
generated chapter url 1
starting request for chapter 1
generated chapter url 2
starting request for chapter 2
received chapter 1
received chapter 2
generated chapter url 3
generated chapter url 4
starting request for chapter 3
starting request for chapter 4
received chapter 3
received chapter 4
*/