Yes, WooCommerce handles attributes differently when your product has a lot of variations (more than 40). If you want, you can increase this threshold to any number by adding the following code snippet to the functions.php file in your child theme
Another question I have is that when a ‘colour’ attribute is out of stock it goes a shade lighter. So that red actually looks pink. Is there a way to have a line through it or an X over it? It’s a little confusing.