Thank you Ed. I have filed a bug as you suggested. MKAnnotationView loses symbol configuration during rendering - FB16957449

It appears that the limitation is at the view builder/container level. Adding another ZStack at the top level and splitting the .onChange calls fixes/addresses the error. Thank you to my son who suggested the fix. var body: some View { ZStack { ZStack { // View code } .onChange() // 1 ... .onChange() // 9 } .onChange() // 10 ... .onChange() // 14 }

@darkpaw The point I tried to make was there appears to be a functional limit now as to how many .onChange calls you can have in a file that did not exist with the deprecated call. I can make ANY 9 of 13 updated .onChange calls work, just not all 13 at once. The code changes themselves are trivially simple: iOS 16: .onChange(of: modeSelection) { newValue in workout.modeSelection = newValue settingsModified = true } iOS 17: .onChange(of: modeSelection) { workout.modeSelection = modeSelection settingsModified = true }

muscleStrength should be an array of HKWorkout. Since it appears to remain initialized, I suggest adding a print("workouts: (String(describing: workouts))") above DispatchQueue.main.async to see what your HKSampleQuery is actually returning.