Why doesn't choosing default values ​​in woocomerce variations work?

Question

Electronic commerce

In general, there is a store on WP + WOO + AVADA, from the variations for each product - color (green, red, blue) and size (42,44,46,48,50)
On the product page, it is possible to select the desired color and the size. But the color of the product only changes when I choose and size. for example By default, the product is green, its variations are blue and red, I choose red and the image of the product remains green, but if I choose any of the sizes, the image changes to the desired color.
In fact, this is correct and logical in terms of variations. Because I have fifteen of them and you need to change the image of the product when all the conditions for the variation are selected.
But this is not entirely logical in terms of using the site.
This issue would be resolved if the default variation value worked. And it is not. Well, that is, I have already selected the color and SIZE I need, and I calmly choose a different color, and the image of the product changes as the conditions for variation are met.
And so, the choice of values ​​by default does not work. How to turn it on?