we have very unusual behaviour during our process of producing messages to the RH AMQ Broker.

We have a setup where 50000 messages are produced from the Java application using Artemis client version 2.28.0.redhat-00012.

Messages are committed in the bulk of 10,000 messages with SESSION_TRANSACTED acknowledgement mode. After we run tests several times and send those 50,000 messages several times to the queue, it happens that the messages from the last commit (the last bulk of 10,000 messages) are not present in the AMQ Broker, and those messages are lost. Behaviour is very non-deterministic, and we cannot say when this behaviour will occur. Sometimes it happens after 3 iterations of those 50k messages, sometimes after 20, but it definitely occurs, and that is the issue because it breaks the at-least-once delivery promise. Every commit lasts for 30 seconds but ends successfully, including the last one, but the last one is missing messages!