ios – HKStatisticsCollectionQuery initialResultsHandler returns nil results for one specific user — read auth granted, data exists, survives reinstall

Environment: iPhone 13 Pro, iOS 26.5. Affects a single user out of many; cannot reproduce on any of our test devices.

We use HKStatisticsCollectionQuery to read step counts for a statistics screen. For one specific user, the query’s initialResultsHandler appears to deliver results == nil (the success branch never runs), so our completion is never called and the screen shows an infinite spinner.

func getDayHourlySteps(currentDay: Date, completion: @escaping ([HKStatistics]) -> Void) {
    let anchorComponents = Calendar.current.dateComponents([.day, .month, .year, .hour], from: currentDay)
    let anchorDate = Calendar.current.date(from: anchorComponents)!
    var interval = DateComponents(); interval.hour = 1

    let manualPredicate = NSPredicate(format: "metadata.%K != YES", HKMetadataKeyWasUserEntered)

    let query = HKStatisticsCollectionQuery(
        quantityType: HKQuantityType.quantityType(forIdentifier: .stepCount)!,
        quantitySamplePredicate: manualPredicate,
        options: .cumulativeSum,
        anchorDate: anchorDate,
        intervalComponents: interval
    )
    query.initialResultsHandler = { _, results, error in
        guard let results else {
            // For the affected user we suspect we land here (results == nil).
            // What HKError shows up here? (we are adding logging now)
            return
        }
        // ...enumerate & completion...
    }
    healthStore.execute(query)
}

What we’ve confirmed / ruled out:

• Read authorization for stepCount is granted (the user toggled it ON in the HealthKit sheet on video).

• The Apple Health app shows step data for this user (so data exists).

• A coarser query (2-year interval) for the same user succeeds, while the hourly query appears to fail — same type / predicate / options / auth.

• Symptom persists across app reinstall and device reboot, and re-granting Health permission.

• Permission denial returns empty results (per Apple docs), not an error — so this isn’t simple denial.

• Not errorDatabaseInaccessible as far as we can tell (foreground, device unlocked).

Questions:

1. What can cause HKStatisticsCollectionQuery.initialResultsHandler to return results == nil (with an error) persistently for one device/account, when read auth is granted and data exists?

2. Can errorHealthDataRestricted occur without an MDM/supervised profile (i.e., on a normal consumer device)? What device/account states actually trigger it?

3. Is it expected that a coarse-interval query succeeds while an hourly-interval query on the same type fails for the same user?

We’re adding logging of the actual HKError code + authorizationStatus for the next occurrence, but would appreciate any insight on what conditions produce this.