JSON generator problem index doesn't implement correctly

Question

Hi I've got a problem who drive me crazy. I want to generate a JSON file of 9999 elements, I'm currently using this web https://json-generator.com/. I use 'index' to implements number on my JSON file the problem is that one of the index doesn't work and doesn't implement correctly and i dont how why. There is some code to understand my problem.

There is the original code to generate the JSON file :

[
'{{repeat(9999)}}',
 {
 file_path: 'C:/Users/Maxime Guenneteau/Desktop/Open Sea Collection/Into the depth of infinity/Images/frctl_{{index(0,9999)}}.png',
 nft_name : 'Fractal #{{index(0,9999)}}',
 external_link: "",
 description: 'Mandelbrot Fractal N°{{index(0,9999)}}',
 collection: 'Into The Depth Of Infinity',
 properties: '', 
levels: [{'name': 'Number', 'from': '{{index(0,9999)}}', 'to': 9999 }],
 unlockable_content: false,
 explicit_and_sensitive_content: false,
 supply: 1,
 blockchain: 'Ethereum'}]

The index of the levels attributes doesn't implement correctly:

 {
"file_path": "C:/Users/Maxime Guenneteau/Desktop/Open Sea Collection/Into the depth of infinity/Images/frctl_2480.png",
"nft_name": "Fractal #2480",
"external_link": "",
"description": "Mandelbrot Fractal N°2480",
"collection": "Into The Depth Of Infinity",
"properties": "",
"levels": [
  {
    "name": "Number",
    "from": 0,
    "to": 9999
  }],
"unlockable_content": false,
"explicit_and_sensitive_content": false,
"supply": 1,
"blockchain": "Ethereum"},{
"file_path": "C:/Users/Maxime Guenneteau/Desktop/Open Sea Collection/Into the depth of infinity/Images/frctl_2481.png",
"nft_name": "Fractal #2481",
"external_link": "",
"description": "Mandelbrot Fractal N°2481",
"collection": "Into The Depth Of Infinity",
"properties": "",
"levels": [
  {
    "name": "Number",
    "from": 0,
    "to": 9999
  }
],
"unlockable_content": false,
"explicit_and_sensitive_content": false,
"supply": 1,
"blockchain": "Ethereum"},

As we can see the Number from 0 to 9999 should implement like the other index but don't.

Thank you for your help