Hello,
Please note that "checkout / notice" is now deprecated in HikaShop 3.x ; that view is still in the "legacy" mode of HikaShop but is not use anymore but the new system.
Afterwards, I don't see any code in HikaShop 3.x or in HikaShop 2.6.3 which indicate that the canonical URL is generated.
But I can see something at the very beginning in the view
$doc = JFactory::getDocument();
$doc->setMetaData( 'robots', 'noindex' );
So the page should not be indexed by robots or else.
And I opened the same page as you in my local website and in our demo website
https://demo.hikashop.com/index.php/en/hikashop/products-listing/display-in-list/checkout/notice/cart_type-wishlist/tmpl-component
There is no any mention of "canonical".
So, as Nicolas noticed previously, it is not HikaShop which generate that but something else
I don't see why HikaShop would generate these links.
I've never seen that.
It looks like something linked to the SEF.
And that's very simple to verify ; if you take any page in your website you will see
<!doctype html>
<html xmlns:fb="https://www.facebook.com/2008/fbml" xmlns:og="http://ogp.me/ns# " xmlns:fb="http://ogp.me/ns/fb#" xml:lang="en-gb" lang="en-gb" >
<head>
<link rel="canonical" href="http://www.p3proswing.com/site3/pro-economy/product" />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
With the canonical define at the very first element in the head.
While in your "notice", you can see strange things :
<!doctype html>
<html xml:lang="en-gb" lang="en-gb" >
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
And with the canonical later, with reversed parameters between "rel" and "href"
<title>ProX Lite</title>
<link href="https://www.p3proswing.com/site3/site3/prox-lite/checkout/notice/cart_type-wishlist/tmpl-component" rel="canonical" />
Due to the unconsitency and while HikaShop is using Joomla core to push his data (and there is no canonical generated for that page) ; I'm sorry but that's not related to our component and our support.
I hope that you will find the source of your issue.
Regards,