Magento 2.2.8 .I have created Configurable product with Color + Size attribute. Product price is not update When select(Click) attribute on Product details page. I am using Luma theme.
You have not provided information that how you have created variations. Have you assigned price to different price to all variants?
I have created configurable product with 4 variants as you shown with 2 scenario. I have used Magento 2.2.8(CE).
Have not assigned price(in this case it will take same price as configurable) and checked that price is not updated as you shown.
Have changed price of 1 variant. Checked that when I select price with different variant, it changes price.
It's working as expected. So please check after changing price in variants.