May 07, 2020
Release blocking defects potentially add lots of churn to a sprint development cycle. These sorts of defects are ones in which the release cannot continue since the application is in a state where business cannot function.
If one looks at a release from an overall perspective, the main goal of a software release is to release new features.
Each feature should allow the user to complete an end goal, whether it be buying a product on an e-Commerce site, or reading an article.
A release blocking defect would be one where the site does not load, or the user is unable to checkout with their shopping cart, or the content of a blog post does not render.
A release blocking defect is not something such as a certain pixel spec is off or there is a minor UI issue. These kinds of things can be fixed post-release.
This website talks about sensical approaches to QA testing and how to really know that your application does what it needs to do day in and day out.