Why does product variation disappear when changing colors?

[Sebasite]

Is simple but complicated, 
I have a product is positive stock and i put that have two colors and when you change from one to other color it despaired option to buy and put quantity to purchase, if you reload than is okay but if you change again color happen the same.
https://revolutex.co/products/bb30-for-shimano?_pos=1&_sid=8abfbd366&_ss=r

i try disconnect all app-s and is the same i try in different computer and browsers and is the same.
I hope that someone have solution for me.

[deepaksharma]

It is an script error, it is not updating the page live when we change the variant we need.

I suggest you contact the theme developer or the concern person who provided this theme to you, or contact any shopify developer to get it fixed.

Hopefully, it will help you. If yes then Please don't forget to hit Like and Mark it as the solution!

[tim]

In your global.js theme file there are 2 functions -- updateStocks and updateStock which look very similar, but target different elements.

I would recommend to:

1)  make a copy of your current theme

2) comment out call to updateStocks  inside function onVariantChange

There are other thing which need improvement, but this would be a reasonable first step.