Hi,
If the module you're using is a HikaShop content module, then the problem must come from a view override of your template which doesn't support canonical URLs and you would have to check with your template provider.
If the module you're using is not a HikaShop content module, then the problem is with the module itself which doesn't support canonical URLs while it should. So you'll have to contact the developer of the module so that they can add that support.
In any case, the HikaShop content module do support canonical URLs itself and there is no reason the URL wouldn't change unless you have some caching in your website and you didn't clear it after activating the canonical URLs.