The issue below affects every partner app embedding our SDK, so we'd appreciate DTS taking a deeper look. We're happy to open a code-level support request and provide screen recordings and a sysdiagnose. Details are in FB25326312. We ship an SMS filtering SDK (a Message Filter app extension) that partner apps embed. Password AutoFill is treating the SDK's messagefilter: associated domain as a credential domain for the host app, so unrelated saved logins appear on the partner app's sign-in screen. Configuration Apple validates Message Filter network deferral against the containing app (an unauthorized containing app gets ILMessageFilterError.Code.networkURLUnauthorized), so the entitlement must be declared on each host app, not the extension: messagefilter:messagefilter.example.comThe AASA file at messagefilter.example.com lists the host app IDs under messagefilter only. It has no webcredentials key. Network deferral works as expected. (The real domain is in FB25326312.) Observed behavior On the host app's sign-in screen, saved logins for the SDK provider's domain (example.com) are suggested in the QuickType bar and the QuickType suggestions list: No webcredentials: domain: only example.com logins are suggested. App's own webcredentials: domain added (valid AASA entry): the app's logins appear, but example.com logins are still suggested alongside them. Password managers Reproduces with Apple Passwords and third-party password managers (tested with 1Password, Dashlane, and Norton Password Manager): Credential providers appear to receive the messagefilter domain in the serviceIdentifiers array passed to prepareCredentialList(for:). Some use only the first identifier, others use all of them. QuickType suggestions come from iOS itself, so the unrelated credentials appear regardless of which password manager is used. Seen on iOS 26 and iOS 27 in a production partner app. Questions Is it intended that a messagefilter: domain contributes to Password AutoFill credential matching? Is there a supported way to exclude it from AutoFill without breaking Message Filter network deferral?