We plan 2 week sprints with all tasks and bugs as much as we can. Every once in a while our QA Lead will assign the developers "bugs" mid-sprint for UI inconsistencies or non-emergency (or what he perceives as an emergency that actually isn't).
This is really frustrating to me, as my tasks of late are dealing with a new product about to be released and then I get a "bug" assigned to me about how the QA Lead doesn't like the layout of a registration form on a web app I haven't touched in who knows how long and I need to fix it right now.
I guess that my question is actually this: What is the "official" definition of a bug, what kinds of bugs are appropriate to interrupt planned tasks to fix and what can I push back on?