diff --git a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/poly-stlc/3.diff b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/poly-stlc/3.diff
index a35277dceb..608aae3314 100644
--- a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/poly-stlc/3.diff
+++ b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/poly-stlc/3.diff
@@ -6,3 +6,8 @@
 <   [(typeof Γ M (σ → σ_2))
 ---
 >   [(typeof Γ M (σ_2 → σ))
+294a295,298
+> (define small-counter-example
+>   (term ((λ (x int) [nil @ int])
+>          [nil @ int])))
+> (test-equal (check small-counter-example) #f)
diff --git a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/poly-stlc/poly-stlc-3.rkt b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/poly-stlc/poly-stlc-3.rkt
index c9e7f6f76d..69187abaed 100644
--- a/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/poly-stlc/poly-stlc-3.rkt
+++ b/pkgs/redex-pkgs/redex-examples/redex/examples/benchmark/poly-stlc/poly-stlc-3.rkt
@@ -292,3 +292,7 @@
         (generate-term poly-stlc M #:i-th index)
         (set! index (add1 index))))))
 
+(define small-counter-example
+  (term ((λ (x int) [nil @ int])
+         [nil @ int])))
+(test-equal (check small-counter-example) #f)