Bootstrap 4: Dropdown menu href link not going to href location

I had this same problem just yesterday and to fix it you need to remove the data-toggle="dropdown" from the Testing menu parent span.

So change the

<span class="dropdown-toggle" id="navbarDropdownMenuLink" data-toggle="dropdown">
    <a href="https://google.com">Testing Menu</a>
</span>

to

<span class="dropdown-toggle" id="navbarDropdownMenuLink">
    <a href="https://google.com">Testing Menu</a>
</span>

Just be cautious about the hovers, especially on mobile menu. If you have a separate clickable caret then it should be fine.