Parallax img not working, but full screen is?

I have recently downloaded and installed your pro package and followed the guidance for Parallax, the full screen image and functionality seems to work ok, however when trying to use the parallax utility within a paragraph setting, the image is static.

This is the same when using my own image or one of yours.

> <div class="jarallax-keep-img float-md-left mr-md-4 mb-4 mb-md-0"
> data-speed="0.5"> <img class="jarallax-img"
> src="/images/1_homepage_carousel_bg_4.png" alt="" width="500"> </div>
> <p> my text here................</p>
> <div class="jarallax-keep-img float-md-right ml-md-4 mb-4 mb-md-0"
> data-speed="0.8"> <img class="jarallax-img"
> src="https://mdbootstrap.com/img/Photos/Horizontal/Nature/full
> page/img (14).jpg" alt="" width="400"></div>

I have placed the following below the code as per your instructions

<script>
    /* init Jarallax */
    jarallax(document.querySelectorAll('.jarallax'));

    jarallax(document.querySelectorAll('.jarallax-keep-img'), {
        keepImg: true,
    });
</script>

Alas the images are just static. Am I missing something here? Other javascript works on the page without issue too.

Any pointers appreciated.