gh attestation verify fails for v5.45.8 Windows release (both --repo and --owner policies)

[zer0-kn0wledge]

Summary
gh attestation verify fails to validate the release attestation bundle
for the Windows x86_64 build of v5.45.8, using both --repo railwayapp/cli
and the looser --owner railwayapp policy. Verifying online (without
--bundle, letting gh query GitHub's attestation API directly) also fails
with a 404 — no attestation found for the artifact's digest.

Environment

• gh version: gh version 2.92.0 (2026-04-28)
• OS: Windows 11, PowerShell
• Architecture: x86_64/AMD64

Artifact

• File: railway-v5.45.8-x86_64-pc-windows-msvc.zip
• Attestation bundle: railwayapp-cli-attestation-43872608.sigstore.json
  (downloaded from the same release page)
• Digest: sha256:3983807554909567d4c24a39ab470119b55ed972161ecd245dfdaeab210ca053
• Attestation predicate type (read from the bundle directly):
  https://in-toto.io/attestation/release/v0.2

Steps to reproduce

1. Online verification (no local bundle):
   gh attestation verify railway-v5.45.8-x86_64-pc-windows-msvc.zip --repo railwayapp/cli

   Result: HTTP 404 Not Found — no attestations found via the GitHub API
   for this digest.

2. Offline verification against the bundle shipped on the release page,
   scoped to the exact repo:
   gh attestation verify railway-v5.45.8-x86_64-pc-windows-msvc.zip --bundle railwayapp-cli-attestation-43872608.sigstore.json --repo railwayapp/cli --predicate-type "https://in-toto.io/attestation/release/v0.2"

   Result:
   Attempting verification against issuer "GitHub, Inc."
   Failed to verify against issuer "GitHub, Inc."
   ✗ Sigstore verification failed
   Error: verifying with issuer "GitHub, Inc."

3. Same command, loosened to organization-level matching only:
   gh attestation verify railway-v5.45.8-x86_64-pc-windows-msvc.zip --bundle railwayapp-cli-attestation-43872608.sigstore.json --owner railwayapp --predicate-type "https://in-toto.io/attestation/release/v0.2"

   Same failure — fails even against the broad
   ^https://github.com/railwayapp/ SAN regex, not just the
   repo-specific one.

Expected behavior
Either the online API should have a record of this artifact's attestation,
or the offline bundle shipped alongside the release should verify
successfully against the railwayapp org/repo identity.

Question
Is the release signing pipeline (GoReleaser-based, given the predicate
type) issuing certificates through a Fulcio instance that isn't one of
the two gh attestation verify checks against (sigstore.dev public-good
and GitHub's own)? If so, is there a documented way to verify these
release artifacts that actually works — e.g. a specific --cert-oidc-issuer
value, or is cosign verify-blob with different flags the intended path
for these bundles?

I want to confirm this release is legitimate before running it, and
would appreciate guidance on the correct verification method for your
release artifacts specifically.