WeatherKit always fails with WDSJWTAuthenticatorServiceListener error 2 (JWT token) despite correct entitlement & capability

WeatherKit's weather(for:) always fails on both a real device (iPhone, iOS 26) and the Simulator. The error is:

WeatherDaemon.WDSJWTAuthenticatorServiceListener.Errors error 2

Device console shows: [AuthService] Failed to generate jwt token for: com.apple.weatherkit.authservice with error: ...Errors Code=2 [WeatherService] Encountered an error when fetching weather data subset ... Code=2

The network reaches weatherkit.apple.com, but JWT token generation fails.

What I have already verified (so this does NOT look like a project misconfig):

1. WeatherKit capability is enabled on the App ID (explicit App ID, not wildcard), enabled over a week ago.
2. The signed app binary AND the embedded provisioning profile both contain com.apple.developer.weatherkit = true (verified with codesign -d --entitlements and security cms -D).
3. I removed and re-added the WeatherKit capability and let Xcode regenerate the provisioning profile. No change.
4. Apple Developer Program membership and all agreements are active; the app is registered in App Store Connect.
5. Device is signed into an Apple Account, date/time is automatic, no VPN / iCloud Private Relay / Lockdown Mode.

Bundle ID: com.hiroaki.pukapuka Team ID: C7ZK5K3WFA

Since every entitlement/capability/account setting is correct, the JWT auth failure (error 2) appears to be server-side. How can I get the WeatherKit service provisioning for this app investigated? (Apple Developer Support case: 102905491144)

Any guidance appreciated.