Customers want to return items without emailing support. What is the first version you would ship?
Answer it out loud before you open anything. The value of the flags below is in comparing them to what you actually said.
The situation behind the question
Today returns happen by email: support checks the order, emails a label, and finance issues the refund when the parcel arrives. The PM's spec includes a returns portal, label generation via the carrier API, reason codes, exchanges, store credit and automatic refunds.
What it is really testing
Whether the candidate cuts scope by the question the first version has to answer, not by removing polish from the full design. The full spec is several quarters of work; the first version should find out whether customers use self-service and where the process actually hurts.