I'm experiencing a strange behavior in Firefox 75 with the following code:

**HTML:**

```
<html>
<body>

<div>
Lorem ipsum dolor sit amet consectetur adipiscing elit sociis vivamus euismod, netus arcu pulvinar egestas cras commodo fames dui nostra tortor quam, class duis sagittis fusce pellentesque conubia ornare venenatis hac. Quis pretium nulla ad nisi aliquam euismod nunc, consequat fermentum sociis eros felis tempus, tortor a risus dignissim fusce facilisis. Fermentum erat eget libero tellus semper gravida enim rhoncus, placerat natoque mauris sollicitudin class eros tincidunt augue volutpat, penatibus vel interdum nunc cubilia taciti dictumst.
...
(the rest is omitted for brevity)
</div>

<a rel="nofollow" href="#" class="scroll-to-top-link">
    Go to top link
</a>

<button class="scroll-to-top-button">
    Go to top button
</button>

</body>
</html>

```

**JS:**

```
( function() {
    'use strict';

    // Feature Test
    if ( 'querySelector' in document && 'addEventListener' in window ) {

        var goTopBtnLink = document.querySelector( '.scroll-to-top-link' );
        var goTopBtnButton = document.querySelector( '.scroll-to-top-button' );

        var nativeSmoothScroll = function () {
            window.scroll({
                top: 0,
                left: 0,
                behavior: 'smooth'
            });
        };

        goTopBtnLink.addEventListener( 'click', function( e ) {
            e.preventDefault();
            nativeSmoothScroll();
        });

        goTopBtnButton.addEventListener( 'click', function( e ) {
            nativeSmoothScroll();
        });

    }

} )();

```

The page has a scroll-to-top link and a scroll-to-top button at the bottom. If I click the link the page scrolls smoothly to the top. When I click the button, too, but only the first time. In subsequent times, the page scrolls too fast, ignoring the `behavior: 'smooth'` option.

I've put the whole code on a fiddle:

<https://jsfiddle.net/mf4rz8hj/9/>

Chrome is not showing this behavior.
Any ideas?