Yes... browsers have cookie size limitations. It isn't a bug as much as a limitation. It would probably vary based on the browser you use but there will always be a limit.
We might be able to work on it to decrease the footprint of the cookie and get the limit up, but at some point you are always going to run into a cookie size limitation.
A solution for that is to store a unique ID for the customer in a cookie, but then save the cart into the database. Then it can function as if it were a cookie based cart and stay populated without login or registration but without inherent cookie size limitations.