Q:

Heroku App - Popper not found (Heroku can't see popper.js)

I've recently deployed my website to Heroku. It's simple static website using Bootstrap, jQuery and Popper. But when I deployed it to Heroku it shows me an error:
Uncaught TypeError: Bootstrap tooltips require Popper.js
Npm install directly on Heroku is not working. Adding CDN is not working. I can see that popper is installing successfully, but then nothing changes, like it was before.
package.json:
{
  "name": "...",
  "version": "1.0.0",
  "description": "...",
  "main": "index.html",
  "scripts": {
    "start": "harp server --port $PORT"
  },
  "author": "...",
  "dependencies": {
    "harp": "*",
    "bootstrap": "^4.1.3",
    "jquery": "^3.3.1",
    "popper": "^1.0.1"
  }
}

A:

So, I've made changes to my main index.html: I've deleted popper.js cdn, installed popper.js once again via npm, disable auto deploy at heroku, pushed my changes to repo, build manually once again at Heroku and now problem is no longer visible. I really don't know the reason, but now everything is fine.

