diff --git a/conductor/src/main/java/com/bluelinelabs/conductor/Backstack.kt b/conductor/src/main/java/com/bluelinelabs/conductor/Backstack.kt
index 34158303..9d397499 100644
--- a/conductor/src/main/java/com/bluelinelabs/conductor/Backstack.kt
+++ b/conductor/src/main/java/com/bluelinelabs/conductor/Backstack.kt
@@ -16,11 +16,11 @@ internal class Backstack : Iterable<RouterTransaction> {
 
   fun root(): RouterTransaction? = backstack.lastOrNull()
 
-  override fun iterator(): MutableIterator<RouterTransaction> {
-    return backstack.iterator()
-  }
+  override fun iterator(): Iterator<RouterTransaction> = backstack.toTypedArray().iterator()
+
+  fun reverseIterator(): Iterator<RouterTransaction> = backstack.reversed().iterator()
 
-  fun reverseIterator(): Iterator<RouterTransaction> = backstack.descendingIterator()
+  fun remove(transaction: RouterTransaction) = backstack.remove(transaction)
 
   fun popTo(transaction: RouterTransaction): List<RouterTransaction> {
     if (transaction in backstack) {
@@ -99,4 +99,4 @@ internal class Backstack : Iterable<RouterTransaction> {
   companion object {
     private const val KEY_ENTRIES = "Backstack.entries"
   }
-}
\ No newline at end of file
+}
diff --git a/conductor/src/main/java/com/bluelinelabs/conductor/Router.java b/conductor/src/main/java/com/bluelinelabs/conductor/Router.java
index 7c4f5ac6..1f913e7d 100644
--- a/conductor/src/main/java/com/bluelinelabs/conductor/Router.java
+++ b/conductor/src/main/java/com/bluelinelabs/conductor/Router.java
@@ -193,7 +193,7 @@ public boolean popController(@NonNull Controller controller) {
                 RouterTransaction transaction = iterator.next();
                 if (transaction.controller() == controller) {
                     trackDestroyingController(transaction);
-                    iterator.remove();
+                    backstack.remove(transaction);
                     removedTransaction = transaction;
                 } else if (removedTransaction != null) {
                     if (needsNextTransactionAttach && !transaction.controller().isAttached()) {