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)