Functional bugs are related to functionality. If a button doesn’t work, if the search doesn’t react to the user input, if an app crashes, or if a product detail page isn’t properly displayed – it’s a functional issue. Every time you click and the website/app doesn’t respond as it should, it’s probably a functional issue.
If there are elements out of place or pictures with bad quality, it is not a functional bug.
Functional bugs have three priorities:
Low: Minimal impact on user experience
High: Serious impact on user experience, but doesn’t prevent the function of the app or website.
Critical: Preventing a function of the app or website, Causes a potential loss of income for the company running the app or website. e.g. an app crash.
Critical issues like crashes etc. should contain crash logs as part of the documentation.
Edge case bugs are never critical, even if they are crashes.
An edge case would be anything that does not reflect typical user behavior. A good example would be repeatedly opening and closing menus. Basically, every bug that is forced is an edge case.
Application blocked by SmartFilter / Virus scanner
If the execution of an app is blocked by a smartFilter or by a virus scanner, this is no bug. Especially if it is a staging environment or a beta version of an app.