A web-identity role session was keyed on its bare OIDC subject until
owners became issuer-scoped. Its sessions now carry the scoped aws:userid
but no asserted issuers, so the legacy subject check never applied and the
session lost the table buckets and namespaces it had created. Read the
configured issuer set for such sessions.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>