diff --git a/project.clj b/project.clj
index e027093..0989153 100644
--- a/project.clj
+++ b/project.clj
@@ -30,7 +30,7 @@
 
   :profiles {:dev {:dependencies
                    [[org.clojure/test.check "0.9.0"]
-                    [org.clojure/clojure "1.8.0"]
+                    [org.clojure/clojure "1.9.0"]
                     [org.clojure/clojurescript "1.9.229"]]}
 
              :test {:dependencies [[org.clojure/clojure "1.7.0"]]}}
diff --git a/src/clj/com/rpl/specter.cljc b/src/clj/com/rpl/specter.cljc
index a69f1e8..29d1ef1 100644
--- a/src/clj/com/rpl/specter.cljc
+++ b/src/clj/com/rpl/specter.cljc
@@ -892,10 +892,10 @@
     (transform* [this structure next-fn]
       (let [select-result (compiled-select late structure)
             transformed (next-fn select-result)
-            values-to-insert (i/mutable-cell transformed)]
+            values-to-insert (i/mutable-cell (seq transformed))]
         (compiled-transform late
                             (fn [_] (let [vs (i/get-cell values-to-insert)]
-                                      (if (seq vs)
+                                      (if vs
                                         (do (i/update-cell! values-to-insert next)
                                             (first vs))
                                         NONE