Our app signs users up through ASWebAuthenticationSession (not ephemeral). The sign-up page is a normal HTML form that posts to our server. When sign-up succeeds, the server redirects to our custom-scheme redirect_uri, which closes the session, as expected.
When the user types a password and submits, iOS shows the "Save Password?" modal inside the session. From there, iOS 26 and iOS 27 behave differently:
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iOS 26.5: iOS waits. The form isn't sent until the user answers the modal. Then the request goes out, the redirect closes the session, and the password has been saved.
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iOS 27.0 and 27.2 beta 2: iOS doesn't wait. The form is sent right away, the redirect closes the session in under a second, and the modal disappears with it. The user never gets to tap Save.
Things we checked:
- Same server, same page, same device, same app build. Only the iOS version changes the result.
prefersEphemeralWebBrowserSessionis off.- Safari itself never waited on neither versions. The waiting only happened inside
ASWebAuthenticationSession. - Saving passwords still works on the device otherwise, and every test used a new account and password.
Questions:
- Is the iOS 27 behaviour intended? If so, is there any supported way to let the user answer the sheet before the redirect closes the session?
- If it's a bug, is it tracked somewhere?
The only fix we've found is to show an extra page after sign-up and only redirect from there, which adds a step for every user. We'd rather not ship that if the iOS 26 behaviour is coming back.