This may be caused by a function I added in the latest version of the plugin which delays showing the audio players until the page is loaded. This is intended to prevent the players showing with the WP default styles and then changing after all the files to make up the page are loaded. If this is the cause, the audio players are not actually taking any longer to load; the wait before the players display will depend on the overall weight of all the files making up the page as well as the connection speeds.
If you prefer the previous behaviour of the plugin, you can try removing this delayed loading by removing the function. You can do this by adding the following line to the functions.php of your child theme or a custom functions plugin: