Check your topics, sol.topics and sol.queue properties in the solace.properties (or solace_sink_properties.json file if using the connector in distributed mode)
The default config, shown below, in the repo shows how to send the message from the “solacetest” topic in Kafka to 3 topics and one queue in solace which would explain why you’re seeing message discards if you’re only subscribing to one of them.
topics=solacetest
sol.topics=soltest, soltest1,solacetest2
sol.queue=testQ