Bootstrap 4 carousel problem in other browsers but not Google Chrome - google-chrome

Question

I have a problem with the carousel from Bootstrap 4.3.1. Bootstrap.css is not customised. It works fine in Google Chrome, but in Firefox and Internet Explorer it has a problem with scaling the pictures into a smaller size?
You can see the problem here on the landing page: https://e90-parts.de/
Could you help me to fix it, please?
Here is the code. It's an edited version from the example on the Bootstrap page.
<div id="welcome" class="carousel slide" data-ride="carousel">
<ol class="carousel-indicators">
<li data-target="#welcome" data-slide-to="0" class="active"></li>
<li data-target="#welcome" data-slide-to="1"></li>
<li data-target="#welcome" data-slide-to="2"></li>
</ol>
<div class="carousel-inner">
<div class="carousel-item active">
<img
src="https://www.kohl.de/webshop/media/image/20/7d/60/20685035c8a385247a18.jpg"
class="d-block w-100"
alt="..."
/>
<div class="carousel-caption d-block">
<h5>Teileauswahl</h5>
<a class="btn btn-primary" href="#Kategorien">Kategorie auswählen</a>
</div>
</div>
<div class="carousel-item">
<img src="images/parts/8273.png" class="d-block w-100" alt="..." />
<div class="carousel-caption d-block">
<h5>Navigationssysteme</h5>
<a href="index.php?site=parts&page=navi" class="btn btn-primary"
>Android 9.0 Navis</a
>
</div>
</div>
<div class="carousel-item">
<img
src="https://cdn.autodoc.de/thumb?id=7583929&m=0&n=0&lang=de&ccf=21876029"
class="d-block w-100"
alt="..."
/>
<div class="carousel-caption d-block">
<h5>Fahrwerke</h5>
<a class="btn btn-primary" href="index.php?site=parts&page=chassis"
>Fahrwerke</a
>
</div>
</div>
</div>
<a
class="carousel-control-prev"
href="#welcome"
role="button"
data-slide="prev"
>
<span class="carousel-control-prev-icon" aria-hidden="true"></span>
<span class="sr-only">Previous</span>
</a>
<a
class="carousel-control-next"
href="#welcome"
role="button"
data-slide="next"
>
<span class="carousel-control-next-icon" aria-hidden="true"></span>
<span class="sr-only">Next</span>
</a>
</div>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>

Answer 1

problem is solved. It was caused by an external carousel which was included on the page in another file. There was some additional code in the which edited the script and the style from the carousel.