I've been troubleshooting this issue for hours. It seems like the navbar is not collapsing correctly in Bootstrap 4, causing the next list item to display to the right of the navbar-brand text instead of below it like the other items.
<nav class="navbar navbar-fixed-top navbar-dark bg-primary">
<div class="container">
<button class="navbar-toggler hidden-sm-up" type="button" data-toggle="collapse" data-target="#exCollapsingNavbar2" aria-controls="exCollapsingNavbar2" aria-expanded="false" aria-label="Toggle navigation">
☰
</button>
<div class="collapse navbar-toggleable-xs" id="exCollapsingNavbar2">
<div class="nav-item">
<a class="navbar-brand nav-link" href="#">IMGS</a>
</div>
<ul class="nav navbar-nav">
<li class="nav-item">
<a class="nav-link" href="#">About</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Contact</a>
</li>
</ul>
<ul class="nav navbar-nav pull-sm-right">
<li class="nav-item">
<a class="nav-item nav-link" href="#">Sign Up</a>
</li>
<li class="nav-item">
<a class="nav-item nav-link" href="#">Login</a>
</li>
</ul>
</div>
</nav>
I have also created a Codepen showcasing the issue: http://codepen.io/NachoSupreme/pen/xEgwJz. Any help would be greatly appreciated!