I have a setup of two servers running two RabbitMQ instances in HA mode, each acting as an app server as well.

There is a named message queue shared by two C++ consumer apps, and they are using topic exchange.

It all is functioning well (round robin wise) when there are 10 messages per second (or more), but when I trigger a message one by one, the first consumer is always preferred.
The broker is setup with prefetch_count = 5 (tried changing it to 1), and auto_ack.