diff --git a/module/ice-9/guardians.scm b/module/ice-9/guardians.scm
index f5c181748..ef050475b 100644
--- a/module/ice-9/guardians.scm
+++ b/module/ice-9/guardians.scm
@@ -65,6 +65,7 @@
   (define (transfer! in out)
     (match in
       (() (values))
+      ((x) x)
       ((x . in*)
        (let* ((out* (cons x out))
               (out** (atomic-box-compare-and-swap! outbox out out*)))
@@ -83,8 +84,7 @@
          (match (atomic-box-swap! inbox '())
            (() #f)
            (in
-            (transfer! in '())
-            (pop!)))))))
+            (transfer! in '())))))))
   (values push! pop!))
 
 (define (make-guardian)