Thanks, Quinn! You were right, it reproduces. A new project from Xcode's standard iOS App template (no third-party code), same bundle ID, team and automatic signing: the archive succeeds, but the upload fails with the same error on "SignTest.app/SignTest" (ID: ULS7ECZNAN4F3FBZGYCMKFENX4). So it's not Godot. New individual account (Team ID ALUWFZZ6Z9). Certs: Development + Distribution Managed, both from Xcode. Xcode 27.1, macOS 27.0.1, Apple silicon. What should I check next?