There are two sellacious_cart_token in cookies. This seems to happen when - in the same browser's window but in two different tabs - there are in each one two sessions one for user/buyer and the other for admin/vendor backend. In simpler words, that seems to ocurr when I am buying but also has the Sellacious backend open. This generates errors in the Add to Cart flow (since two tokens are present). I would expect system allows to have the two sessions open without issues/confusion at purchasing in the frontend
Using Chrome browser in computer. Check attachment.