Q:

Bootstrap4 Disabled button white instead of supposed color

I am using a bootstrap button on one of my page, that is disabled, and the styling seems to not be working properly 

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.0.0-alpha.6/css/bootstrap.min.css">
<button disabled class="btn btn-primary">suivant</button>
<button class="btn btn-primary disabled">suivant</button>

I tried these 2 ways and the result look like this for both approach: initial look || on Mouse over
EDIT: Important to mention that i only have bootstrap4, no personnal style sheet and no other themes
This is a react Project, className is used instead of class

A:

https://codepen.io/jacobweyer/pen/ybqxBK
I've updated this codepen to show Bootstrap4 buttons with BS4 alpha 6. They look like they show up as intended in and outside of React.
<button class="btn btn-primary">suivant</button>
<button class="btn btn-primary" disabled>suivant disabled</button>

