This isn't a competition. They aren't in a classroom where the professor is asking a trick question. This person wants to hire someone who can spot the bug, understand it, and propose solutions.

Who cares if the candidate comes from a field where this isn't common? That's the point. You want to hire people who would know what to do if they came across it.

It's amazing the amount of hostility here towards a perfectly sensible interview question and process.