Odd rule binding behavior

console.txt

v: c ?e1:  ?e2: puzzle.core.Entry@ebe1e4be
v: c ?e1:  ?e2: puzzle.core.Entry@ebe1e4be
v: c ?e1:  ?e2: puzzle.core.Entry@ebe1e4be
v: c ?e1:  ?e2: puzzle.core.Entry@ebe1e4be
v: b ?e1:  ?e2: puzzle.core.Entry@ebe1e4bf
v: a ?e1:  ?e2: puzzle.core.Entry@ebe1e4bc

core.clj

(ns puzzle.core
  (:refer-clojure :exclude [==])
  (:require [clara.rules :refer :all]))

(defrecord Entry [value])

(defrule make-uniqueness
  "Convert a collection of strings, with duplicates, into a collection of unique strings with no duplicates - appending numbers as needed."
  [?e1 <- Entry (== ?v value)]
  [?e2 <- Entry (== ?v value)]
  [:test (not (identical? ?e1 ?e2))]
=>
  (println (str "v: " ?v " ?e1: " ?e1 " ?e2: " ?e2)))

(defn -main
  "Run the uniqer."
  [& args]
  ;; Create a session
  (let [session (mk-session 'puzzle.core)]

    (-> session
        (insert
          (->Entry "a")
          (->Entry "b")
          (->Entry "c")
          (->Entry "c"))
        (fire-rules))))

project.clj

(defproject puzzle "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.5.1"]
		[org.toomuchcode/clara-rules "0.3.0"]]
  :main "puzzle.core")