Unable to create 'Shared Web Credentials' on fresh TestFlight Install

Hey Apple team (and eskimo 🙏),

Our FinTech app uses iCloud Keychain shared web credentials to store a secure encryption password in iCloud Keychain.

Some of our new users seem to run into an issue where the app fails to successfully create a shared web credential.

All users are required to have the following two settings enabled:

  1. Settings --> Passwords --> Password Options --> Autofill from iCloud Passwords & Keychain

  2. Settings --> Apple D - -> iCloud - -> Passwords and Keychain --> 'Sync this iPhone'

The issue appears to resolve itself when the user restarts their iPhone. We've had this bug 3 times now and would like to understand the root cause.

We have a couple hypotheses:

  1. iOS is failing to verify that the domain for the shared web credential is valid via <domain>/.well-known/apple-app-site-association (and then restarting triggers reverification)
  2. Users were on a version of iOS where it was bugged (and then restarting finally completed an update to a new version). We've verified that the bug happened on 17.0.2 with one user (until they updated and it fixed itself)

Unfortunately without at least an error message it's hard to know what direction to investigate. If you can file this through Feedback Assistant, providing the error or even better device logs, we'd be happy to take a look!

Unable to create 'Shared Web Credentials' on fresh TestFlight Install
 
 
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