Hi,
Edit the brand via the Products>Brands menu and check if you have something in the "canonical URL field of the brand. If you do, try to empty it and that should help.
If you don't, then please check your Joomla menu manager for any menu item of the type "HikaShop categories listing" with the main category being selected is the main brand element (so a listing of the brands).
Also, please provide a screenshot of the settings of the menu item with the alias "Skateshop-Brands" which is actually used by the link.