Root cause is now fully pinned down: HashiCorp published the

v1.16.0

GitHub release tag at 2026-08-26 13:05 UTC (13 minutes before your first merge-queue attempt), but the actual binary artifacts haven’t propagated to

<http://releases.hashicorp.com|releases.hashicorp.com>

yet — `api.releases.hashicorp.com`still returns

"release not found"

for 1.16.0, and the direct download URL still 404s. The latest version actually available there is

1.15.9

.