PhotoKit. Changing iCloudId between devices.

While developing a gallery app, I noticed that the iCloudId can change between devices Phone1 and Phone2, on which iCloud is active.

First, I know the assetId is unstable, but the iCloud ID (

How it can be? I thought it was stable and I could use it for sending, for example as a UUID for a items on BE to prevent duplication.

Could you please explain to me in which cases the iCloudId can change, and what I can use for stable UUID for my internal item to prevent duplication on the BE side?

Additional info:

Phone1:

   - assetId part = B01B27D9-10BE-4C95-BE35-C9A03DBA4006
   - iCloudId part = 39E0E3A6-6A37-4E8E-83E9-C1B837E2E973
  - iCloudId full = 39E0E3A6-6A37-4E8E-83E9-C1B837E2E973:001:ARUcJ2AQQ/nM6BIRu2dq/NSPi61u

Phone2:

    - assetId part = F51B272C-1BE6-41B3-AB54-39E6BDE1C984
   - iCloudId part = F51B272C-1BE6-41B3-AB54-39E6BDE1C984
  - iCloudId full = F51B272C-1 BE6-41B3-AB54-39E6BDE1C984:001:ARUcJ2AQQ/mM6BIRu2dq/NSPi61u
PhotoKit. Changing iCloudId between devices.
 
 
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