What is a Defect correction (SMTM), and why doesn't it need its own approval or new RfC?

It connects directly to TMS and works with normal change to fix defects found in the controlled test phase — allowed only in the test phase (the formal integration-test window, where no new scope is allowed and you technically can't build a new normal change). It's ChaRM's only way to allow new changes in a dedicated test phase.

No approval/new RfC is needed because testing spans the whole release and can't be traced to a specific RfC/normal change — scope is already approved, and dev + test must collaborate to fix.