trying to fetch data from kafka, not being able to use "take"

clj-kafka-test.clj

(defn consumer-config [] {"zookeeper.connect" "localhost:2182"
                          "group.id" (str (java.util.UUID/randomUUID))
                          "auto.offset.reset" "smallest"
                          "auto.commit.enable" "false"})
(defn fetch-first [topic]
  (with-resource [c (zk/consumer (consumer-config))]
    zk/shutdown
    (first (zk/messages c topic))))

(defn always-nil [topic batch-size]
  (with-resource [c (zk/consumer (consumer-config))]
    zk/shutdown
    (take batch-size (zk/messages c topic))))

(fetch-first "test") ;=> #clj_kafka.core.KafkaMessage{:topic "test", :offset 0, :partition 0, :key nil, :value #object["[B" 0xcacb0b3 "[B@cacb0b3"]}
(always-nil "test" 1);=> ()

Notice how every call gets a new "group.id" due to consumer-config being a function (for testing). (first always returns offset: 0 with a message. Shouldn't (take 1 also return the first message ?