I'm wondering if they made the mistake of acknowledging the message before the processing was done. From the article it sounds like their jobs take a long time

I'm wondering if they made the mistake of acknowledging the message before the processing was done. From the article it sounds like their jobs take a long time to run so they may have acked the message to stop RabbitMQ from delivering the message to another worker for retry but IIRC there is a setting that allows you to extend the "lease" time on a message before retry.