We discovered that on iPhones and other mobile devices of Apple’s the preview image of the video would not display. To fix this we need to move the video start point to 1 millisecond in by adding #t=0.001 to the src URL.
Example For ACF Field Getting The Video
<?php
$videoURL = get_sub_field('slider_video');
$videoURL = $videoURL . '#t=0.001';
?>Example For The Video Source Being Hardcoded
<video preload="metadata">
<source src="https://example.com/wp-content/uploads/2022/01/example.mp4#t=0.001" type="video/mp4">
Your browser does not support the video tag.
</video>
