In WooCommerce 3.3 we introduced a new uncategorized category all product will default to when no other category is assigned to them. This is the same behavior that WordPress uses for posts. With that, unfortunately, if your shop is set up to display categories on the shop page then this new uncategorized category will also show up.
Although we give you the possibility to rename the category to whatever you would like, there might be cases where you would like to rather not display this on your shop page. To do that you can simply add the following piece of code to your site via your theme’s functions.php file, or via a custom plugin. Remember to not include the opening tag
<?php if you are adding this to an existing file.