Situation
An intermittent thermal/battery regression appeared on a subset of pre-release devices, serious enough to threaten a hardware release timeline and draw executive attention.
Investigation
Bisected across builds and feature flags, toggling combinations and diffing behavior to isolate the exact failing code path rather than guessing from symptoms.
Root cause
Traced to a specific flag combination introduced in a recent build, only reproducible under a narrow device/config state.
Engineering collaboration
Handed the owning team a confirmed diagnosis and reproduction path, prioritized against the release timeline.
Validation
Verified the fix against the original repro and the regression suite across the affected build set before sign-off.
Communication
Delivered plain-language status to senior stakeholders throughout, translating build-level findings into release-timeline impact.
Lesson learned
Stood up a dedicated L2 specialist group for this regression class, so triage no longer required an ad hoc escalation each time it recurred.