diff --git a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/1.diff b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/1.diff
index fa4c87b271..9a331fea9c 100644
--- a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/1.diff
+++ b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/1.diff
@@ -5,3 +5,7 @@
 106,107d105
 <   [(subst x x v)
 <    v]
+290a289,291
+> (define small-counter-example
+>   (term ((λ (x int) x) 1)))
+> (test-equal (check small-counter-example) #f)
diff --git a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/stlc-sub-1.rkt b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/stlc-sub-1.rkt
index 2e684e4f71..7724ee59ed 100644
--- a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/stlc-sub-1.rkt
+++ b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/stlc-sub/stlc-sub-1.rkt
@@ -286,3 +286,6 @@
         (generate-term stlc M #:i-th index)
         (set! index (add1 index))))))
 
+(define small-counter-example
+  (term ((λ (x int) x) 1)))
+(test-equal (check small-counter-example) #f)