torrentSource threw plain Error for a missing site or a site without an adapter definition, so submitDownload retried to max attempts, left the plan and slot reserved, and sweepReservedPlans re-enqueued it forever (agent runs stayed waiting on goal-settled). Throw SiteError (not_found / unsupported) so the plan fails and the slot is released. Needs image rebuild to take effect. Co-Authored-By: Claude Opus 5.5 <[email protected]>