Apple Watch health expansion faces a launch bug and accuracy scrutiny

Series 12 and Ultra 4 add more frequent heart-rate and HRV measurements, Readiness scoring, and longer battery life, reportedly reaching 50 hours on Ultra 4. Apple released watchOS 27.0.1 to address unexpected restarts, but the bug’s scope and the update’s effectiveness remain uncertain; health accuracy, GPS, step-count features, and the absence of advanced blood-pressure monitoring remain under review.