Hi Ziqiao, thanks for your response. We added the MRE and a description of the steps to reproduce the issue to the Feedback report. The same MRE and description was previously added to our DTS report (Case-ID: 19755043). We still see the issue on iOS 26.5 and iOS 26.6 latest beta.

Hi Ziqiao, Thank you for looking into this. My apologies for not making that explicitly clear in the original post. Yes, I can confirm that the workout is definitively not saved, resulting in complete data loss. After the finishWorkout(completion:) handler executes (returning a nil workout and nil error) while the screen is locked, we unlock the device and verify both inside the Apple Health app and via direct HealthKit queries. The workout does not exist. Per your recommendation, I have just updated our Feedback report and our open TSI case to explicitly highlight this confirmation. Please let me know if there are any other details or specific logs we can provide to help the engineering team!

We fixed it with adding gps data points (by an interpolation of the existing GPS data points). But the underlying issue is that the GPS Route in the Summary page of Apple Health is not show correctly when there are less GPS data points, while the Apple Health app shows the correct route in the Details page (show all workout routes). So the real issue is an Apple Health viewing issue.

It seems that the code sample doesn't show in our post, here is the code that we use to add the location data to the workout, where routeBuilder is of type HKWorkoutRouteBuilder: let workoutRoute = try await routeBuilder.finishRoute(with: workout!, metadata: nil)