How would you troubleshoot a situation where UAT participants keep raising items as defects that are actually new requests?

1. First, check that the acceptance criteria were shared with the testers. Very often the testers were never told what the solution was agreed to do, so they test against personal expectation.
2. Re-baseline the session: publish the scope, the acceptance criteria, and a plain-language description of what is deliberately out of scope for this release.
3. Introduce a simple triage rule at intake: if the behaviour contradicts an agreed acceptance criterion it is a defect; if it asks for something never agreed it is a change request. Apply the rule visibly and consistently.
4. Keep the change requests, do not suppress them. Logging them into the backlog reassures testers that raising ideas is welcome, which is what stops them from mislabelling ideas as defects to get attention.
5. If a large volume of change requests appears, that is a signal in itself — usually that end users were not engaged during discovery. I would flag that to the Product Owner as a genuine adoption risk, not just a testing nuisance.