What is a Shopify app conflict?

A Shopify app conflict happens when two installed apps both modify the same part of your storefront and step on each other. Common forms: two apps inject JavaScript that grabs the same global variable (so the page JS throws and breaks), two apps fire the same analytics pixel (so events double-count), or two apps drop the same widget (so it renders twice). The store usually worked fine until you installed or updated one app, that is the tell.