Problem with Cookie being Cached in Siteground Optimizer

Hi @nomadslyfer
hope you’re fine ? Sorry for the issue you’re facing.
I’ve check the Siteground Optimizer plugin doc and seems they don’t have a way to excude specific cookies from caching. May you can ask their support
Otherwise you can try this snippet

<script>
document.addEventListener("DOMContentLoaded", function(){
  var origLink = document.querySelector("a[href^=\"wg-choose-original=true\"]")
	if(origLink) {
			origLink.addEventListener("click",function(e) { 
				var href = this.href;
				e.preventDefault(); 
				document.cookie = "WG_CHOOSE_ORIGINAL=1; path=/;"; 
				window.location = href;
			});
	}
});
</script>

you can add this snippet on footer for example : https://developer.wordpress.org/reference/hooks/wp_footer/

Regards