diff --git a/racket/collects/racket/private/custom-hash.rkt b/racket/collects/racket/private/custom-hash.rkt
index 71db64bc46..4d0b64c122 100644
--- a/racket/collects/racket/private/custom-hash.rkt
+++ b/racket/collects/racket/private/custom-hash.rkt
@@ -168,10 +168,18 @@
 (define (wrap-key spec key)
   (define wrap (custom-spec-wrap spec))
   (define intern (custom-spec-intern spec))
-  (ephemeron-value
-   (hash-ref! intern key
-     (lambda ()
-       (make-ephemeron key (wrap key))))))
+  ;; Rely on the fact that a wrapped key is never represented as `#f`
+  (define e (hash-ref intern key #f))
+  (cond
+    [(not e)
+     (define wrapped-key (wrap key))
+     (hash-set! intern key (make-ephemeron key wrapped-key))
+     wrapped-key]
+    [else
+     (define wrapped-key (ephemeron-value e))
+     (or wrapped-key
+         ;; Ephemeron was just cleared; try again
+         (wrap-key spec key))]))
 
 (define (hash-check-key who d key)
   (define spec (custom-hash-spec d))