MVC bootstrap navbar not working after running NuGet updates

An MVC app broke after we updated all the NuGet packages. After trying everything I created a new MVC app, updated the NuGet packages and the basic navbar...

<div class="navbar navbar-inverse navbar-fixed-top">
    <div class="container">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
            <a class="navbar-brand" href="/">Application name</a>
        </div>
        <div class="navbar-collapse collapse">
            <ul class="nav navbar-nav">
                <li><a href="/">Home</a></li>
                <li><a href="/Home/About">About</a></li>
                <li><a href="/Home/Contact">Contact</a></li>
            </ul>

<ul class="nav navbar-nav navbar-right">
    <li><a href="/Account/Register" id="registerLink">Register</a></li>
    <li><a href="/Account/Login" id="loginLink">Log in</a></li>
</ul>


        </div>
    </div>
</div>

... looks like this ...

...and clicking the icon...

Any ideas what could be causing this?

Have tried manually adding Bootstrap.css and Bootstrap.js to _Layout.vbhtml, but no difference

Thank you