Why col makes my sticky navbar not working?

Question

I'm trying to have a sticky promotion bar at the top of the website. Any logo just under it. And under the logo a sticky navbar. Promotion & navbar should be col-8.

All works with the sticky function, but when I add 'col-8' at my nav & promotion bar the sticky doesn't works..

I'm using Bootstrap 4.

(Fun fact is that on CodeSandbox it works but not on chrome/safari: https://codesandbox.io/s/stoic-haslett-qyrhn?fontsize=14)

Here is the code:

html {
  scroll-behavior: smooth;
}

body,
* {
  font-family: 'Futura', 'Montserrat', 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
  font: 16px/18px sans-serif;
  background-color: black !important;
  max-width: 100%;
  max-height: 100%;
}

img {
  max-width: 100%;
  max-height: auto;
}


/* ----- Logo ----- */

.logo {
  position: relative;
  top: 50%;
  left: 50%;
  transform: translate(-50%);
  height: 35em;
  max-width: 100%;
  margin: 3em 0 3em 0;
}


/* ----- Promo bar ----- */

.promo-bar {
  text-align: center;
  font-weight: bold;
  background: linear-gradient(to bottom, #e8b923 0%, #e8b923 100%);
  color: #2F2E2E;
  vertical-align: middle;
  font-size: 1.3em;
  padding: 0.5%;
}


/* ----- Navbar ----- */

#navbar {
  background-color: #333;
  text-align: center;
  border-top: 1px solid whitesmoke;
  border-radius: 7px;
  display: flex;
  justify-content: space-around;
  margin: 1em 0 1em 0;
  width: 100%;
}

#navbar a {
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;
  padding: .7em;
  text-decoration: none;
}

.sticky {
  position: sticky;
  top: 0;
  padding: 0 !important;
}

<!-- Promotion bar -->
<div class="col-8 container-fluid sticky" style="z-index: 1">
  <div class="promo-bar ">Réduction -10% en caisse avec le code: "SITEWEB10"</div>
</div>

<!-- Logo Centered -->
<img src="logo.jpg" class="logo">

<!-- Nav Bar -->
<div class="col-8 container-fluid sticky" style="z-index: 1">
  <div id="navbar">
    <a>|</a>
    <a href="#home">Accueil</a>
    <a>|</a>
    <a href="#story">Notre histoire</a>
    <a>|</a>
    <a href="#contact">Contacts</a>
    <a>|</a>
  </div>
</div>

Thank you for the time you will give, and sorry for my bad english.

Answer 1

@DDeveloper's answer helps me to find the solution.

In the first <div>put the sticky function, and in his child the col-8.

Like this:

<div class="sticky">
  <div class="col-8"></div>
</div>