Hi,
There are only three ways that HikaShop can fill in canonical URLs automatically :
- You've configured a mass action to fill them one way or another.
- You've configured the HikaShop product cron update plugin to automatically import a CSV with product data including the product_canonical column.
- You've set the "force canonical URLs on listings" setting of the HikaShop configuration to "Use canonical URL and generate it if missing".
If it's none of that, then either the URLs were already filled before in one of those ways, or you (or someone on your end) entered them manually, or a third party extension is filling them on your website.