If both iCloud Sync and Health Integration are turned on and you use multiple iPhones, there is an important behavior to be aware of.
When a record is saved on Device A → synced to Device B via iCloud → also saved to Health on Device B, HealthKit's internal merge process may run. During this process, Health app data on Device A may temporarily appear to be missing.
It will recover on its own after a short time, but if you want to avoid this entirely, you can turn off Health Integration on the secondary device (the non-primary iPhone).
How to Turn Off Health Integration on the Secondary Device
- On the secondary device, open Settings in Blood Pressure Time.
- Turn off "Health Integration".
Keep iCloud Sync turned on to maintain data sync. Health app data will only be written from the primary device.
Note: This only occurs when both iCloud Sync and Health Integration are on across multiple devices. It does not occur when only one of them is enabled.