Variation issues with Theme Impreza Grid system

Please help because I don’t know if there is a plugin problem here or an Impreza theme. Impreza grid system doesn’t show variation price after option selection and also a button “add to cart” is available even before the option is selected.

Also, variation options disappear at all after products scroll loading.

I don’t know if it’s a plugin issue or theme. And if theme, what error is