Hi,
I don't know why this plugin is adding a canonical URL on the product pages. Especially since the canonical URL it adds on it is only the current page URL, which isn't what a canonical URL is supposed to be.
Here is a discussion about this issue:
github.com/joomla/joomla-cms/discussions/31806
As far as I know, this plugin creates more problems than it solves. I can only recommend deactivating this plugin. If you need canonical URLs in other materials than HikaShop, please use another plugin from the JED.