Hi,
Sorry, we had miseed your thread.
From what I can see, it's probably an issue with the canonical URL.
If you set a canonical URL in the main product information, but not for each language, and you have the "force canonical URLs on listings", then the canonical URL will be used for all the languages and thus, based on the language tag in the URL it will switch to the language of the canonical URL when displaying the page.
So either:
- configure the canonical URL for each language of each product
- turn off the "force canonical URLs on listings" setting in the HikaShop configuration. This won't be a problem for your SEO as the canonical URL will still be the only one referenced by search engines, regardless of the URL used to access the product page.