Cross Function not working properly

Hi Dear Developer, I am facing issue with cross functionality which not working properly on some pages of website. I have mentioned a link of my post where cross function not working when some things out of stock. Please help me as possible how can i fix it

https://www.yiford.com/product/shop-topeview-sideview-silicone-led-channel-system/

The page I need help with: [log in to see the link]