Open Radar

 
Area:
Something not on this list

Summary:
Updating OS (major versions only), resetting, pairing/unpairing the Apple Watch with an iPhone results in absolutely a new device, despite the device correctly recognized everywhere else in the system (like iCloud) and data correctly merged, but HealthKit data remains split and linked to old Apple Watches with the message (This Apple Watch in no longer paired with this iPhone.

Deleting these deletes also past health data, so I'm stuck with multiple ghost Apple Watches as a Source.

Steps to Reproduce:
Pair an Apple Watch with a phone, get some health data.
Unpair/pair again.

Expected Results:
Like with iCloud and other services, the Health data is expected to correctly copy over, or at least merged in the Health App under the same source (after all, it's the same device)

The Health App is expected to correctly recognize the Watch as the same source by:
- Tagging data with a hardware UUID
- Merge or copy old data in the new paired watch and securely remove old data as part of the new pairing process.

Observed Results:
We now have at least an extra Apple Watch as a source in the Health App. Doing this multiple times results in a large list of ghost watches.

Version:
Multiple iOS 9 through 10.3.3
Multiple watchOS from 2 through 3.2.3

Notes:
Unsure if the problem is intrinsic to how iOS/watchOS works and identifies a new Hardware, or if it's with HealthKit.
But there should be a way to merge the Health Data in the same source, maybe have two separated Device IDs, one specific to the hardware, and one for the global name.

For example, the iPhone is correctly displayed as one source, despite upgrading my phone every year.

Configuration:
Multiple iPhones (activated from backup on each upgrade)
2 Apple watches (Series 1 and Series 2)