Question

Finance reconciliation finds ~0.05% of `payment-captured` events never reached the analytics warehouse — gaps with NO matching Kafka record at all (not a consumer gap). No consumer lag, no consumer errors. Dashboards: consumers process every record that exists. The producer side shows a small but nonzero `record-error-rate` and a `buffer-available-bytes` that periodically dips to ~0 during traffic peaks; the producer was recently tuned for throughput — `acks=1`, `linger.ms=20`, `max.in.flight.requests.per.connection=5`, `retries` left at a low value, and `delivery.timeout.ms` fairly short. Brokers had a brief leader election yesterday during the peak window where the gaps cluster. How do you triage and mitigate?