Hi,
This problem is not linked with HikaShop.
You have several menus, several path to access to a product so, several different links.
You can improve the configuration by forcing the menu in hikashop content modules. With it, you would force the product page url.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.