Collections not showing all products and issues with variable products

[Eloise123]

We encountered an issue with our variable products where it was only allowing the first option to be selected and added to the cart despite selecting another option. 

This issue was resolved by making changes to our code however, one of our other collections is now displaying no products even though everything is appropriately tagged and active. Furthermore, new listings aren't appearing in their designated collections, again everything is appropriately tagged and active.

We had a similar issue where our collections were showing up as empty BEFORE we made the changes to our code to solve the variable issue. Shopify online chat was able to instantaneously resolve this for us but the advisor wasn't sure how that had happened in the first place.