Where were the duplicate messages received?

Duplicate messages usually go into a queue or storage where they can be processed again. In Go systems, if a message queue is used (e.g., Kafka, RabbitMQ), duplicates can end up in the same queue due to resending or re-reading without acknowledgment.

To avoid issues with duplicates, idempotent processing is often used — for example, storing unique message identifiers and checking them before processing. This way, duplicate messages can enter the system but do not affect the final result.

If the question is about a specific application, then duplicates could have entered the same queue or a separate log/storage for subsequent analysis.