materialize: [ Navbar Dropdown Menu ] focus bug when hovering over dropdown items

Context

It seems that there is an issue which shows an ugly black/white border when hovering over and then out of a dropdown element which is defined within a navigation bar. It seems that this has something to do with focusing in and out of the dropdown trigger.

I have attached a screenshot which shows the border:

Steps to Reproduce (for bugs)

1. Using the following code (as documented on https://materializecss.com/navbar.html#navbar-dropdown) :

<!-- Dropdown Structure -->
<ul id="dropdown1" class="dropdown-content">
  <li><a href="#!">one</a></li>
  <li><a href="#!">two</a></li>
  <li class="divider"></li>
  <li><a href="#!">three</a></li>
</ul>
<nav>
  <div class="nav-wrapper">
    <a href="#!" class="brand-logo">Logo</a>
    <ul class="right hide-on-med-and-down">
      <li><a href="sass.html">Sass</a></li>
      <li><a href="badges.html">Components</a></li>
      <!-- Dropdown Trigger -->
      <li><a class="dropdown-trigger" href="#!" data-target="dropdown1">Dropdown<i class="material-icons right">arrow_drop_down</i></a></li>
    </ul>
  </div>
</nav>

1. Using the following options for the DropDown initialisation:

        document.addEventListener('DOMContentLoaded', function() {
            let elems = document.querySelectorAll('.dropdown-trigger');
            let options = {
                hover: true,
                coverTrigger: false,
            }
            let instances = M.Dropdown.init(elems, options);
        })

1. Hover over and out of the dropdown element.

2. Within the developer-console, adding the :focus state to the <li>, which surrounds the Dropdown Trigger, will result to the same behaviour.

Your Environment

• Version used: This issue occurred to me in both "@materializecss/materialize": "^1.0.0" and the CDN stated in the documentation (https://materializecss.com/getting-started.html).
• Browser Name and version: Google Chrome Version 88.0.4324.182 (Official Build) (64-bit)
• Operating System and version (desktop or mobile): Linux Mint 20