The NS-570 epoch stamp clears a drain marker that survives a machine
restart — but it assumes every drain-gated action ends in a restart. When
a maintenance action completes WITHOUT recreating the container and the
writer never cancels the drain, the orphaned marker still carries the
current epoch, so the 1s drain watcher honours it forever and the gateway
bounces every inbound message with the 'draining for a maintenance
action' text (observed in the field: a Hermes Cloud instance refused all
Telegram turns for ~3 days).
The marker already records requested_at; now the readers check it. A
marker older than DRAIN_REQUEST_MAX_AGE_SECONDS (1h) reads as stale in
drain_requested() and drain_notification_suppressed(), with a loud
warning log. Leniency mirrors the epoch check: a missing or unparseable
timestamp still reads as drain-active (fail-safe toward quiescing), and
a legitimately long drain keeps a sanctioned keep-alive — re-calling
write_drain_request() refreshes requested_at.
Fixes#85433
kshitij
8855766716