This is how we acknowledge a message
And using this for acknowledgment
flowProp.setAckMode(JCSMPProperties.SUPPORTED_MESSAGE_ACK_CLIENT); This is the publisher
We are using the latest version of the image solace/solace-pubsub-standard:latest using Java and this issue is random, the test fails from time to time (it’s frustrating in CI when the tests fails and we need to rerun them multiple times).
I hope I answered your question.