This reports the timestamp of the most recent automatic threshold recalibration that fired because the interval's high watermark drifted outside its expected upper/lower band. An admin cares because this timestamp tells them exactly when the box last decided its configured alarm thresholds no longer matched real traffic and self-adjusted, useful for correlating with a traffic spike or a provisioning change around that time. For example, this might read '2026-08-05,14:32:10.0' showing the last recalibration happened a few days ago, or return an empty string on a freshly-provisioned PM instance that has never triggered this event.