Producer publishes message to multiple topics

I am new to Kafka and have a basic question, I have installed control center on an ec2-instance and I have two connectors running on two separate ec2-instances (one is source and the other is sink). This kafka cluster has only one broker and 2 user defined topics. I have a spring boot app which uses spring kafka and publishes messages on one topic (for simplicity lets say topic-A) and consumes message from (topic-B). Both topics have only 1 partition. What I am observing is this, whenever producer publishes a message to topic-A the same message also flows to topic-B. This then causes errors in the consumer (deserialization errors). Can someone please confirm whether this setup is correct and why am I seeing this behavior?

The issue was due to misconfiguration in the REST API requests which led to this issue.