This fix only for self hosted videos or videos using the WP Medialements.
Copy below code and paste/append it in WPLMS options panel - Footer - Google analytics code
jQuery(document).ready(function($){
jQuery('.unit_content').on('unit_traverse',function(){
$('video').each(function(){
player = new MediaElementPlayer('video');
$('video').on("play", function() {
player.enterFullScreen();
});
});
});
});
Result :
When user clicks on Play, the player would automatically open in full screen mode :