diff --git a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/5.diff b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/5.diff
index 71f437d907..9472968f38 100644
--- a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/5.diff
+++ b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/5.diff
@@ -6,3 +6,7 @@
 <   [(subst x x v)
 ---
 >   [(subst x y v)
+290a291,293
+> (define small-counter-example
+>   (term ((λ (x int) (λ (y (list int)) (hd y))) 1)))
+> (test-equal (check small-counter-example) #f)
diff --git a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/stlc-sub-5.rkt b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/stlc-sub-5.rkt
index a8a53c2a12..ffdfee4716 100644
--- a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/stlc-sub-5.rkt
+++ b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/stlc-sub-5.rkt
@@ -288,3 +288,6 @@
         (generate-term stlc M #:i-th index)
         (set! index (add1 index))))))
 
+(define small-counter-example
+  (term ((λ (x int) (λ (y (list int)) (hd y))) 1)))
+(test-equal (check small-counter-example) #f)