I have an active site right now that needs some help immediately. It should be really quick for an experienced shopify developer like yourself. I am just lost in the code right now. I am getting the error message "Cart Error We were not able to add this item to your shopping cart because no variant ID was passed to us." On some products that have a size dropdown you are unable to choose a size but you can still add the first size to the cart no problem. For other products that only have two sizes you can choose either size but you get the "no variant was passed error"
Seems like a straightforward issue and would love someone with your experience to solve it.