What is a Secondary Risk?
A secondary risk is a brand-new risk created by your risk response itself. You fixed one problem and your fix invented another — that new one is secondary, and it goes on the register like any other risk.
Keep the exam pair straight: residual risk is what remains of the original risk after the response; secondary risk is a new risk the response created. Different animals, different register entries.
Worked example
To avoid unreliable Supplier A, a construction PM switches the steel order to overseas Supplier B. Problem solved — and a new one born: ocean freight adds a customs-delay risk that never existed before. That customs risk is the secondary risk, and it needs its own response.