diff --git a/src/ADNLPProblems/gulf.jl b/src/ADNLPProblems/gulf.jl
index a7c46954..02630964 100644
--- a/src/ADNLPProblems/gulf.jl
+++ b/src/ADNLPProblems/gulf.jl
@@ -35,7 +35,7 @@ function gulf(
   m = min(m, 100)
 
   function F!(r, x; m = m)
-    for i = 1:n
+    for i = 1:m
       r[i] =
         exp(-abs((25 + (-50 * log(i * one(T) / 100))^(2 // 3)) * m * i * x[2])^x[3] / x[1]) -
         i // 100
diff --git a/test/runtests.jl b/test/runtests.jl
index 539e1012..20befcce 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -45,6 +45,13 @@ include("test_utils.jl")
     end
   end
 
+  @testset "Test for nls_prob flag for $prob" begin
+    nls_prob = eval(Meta.parse("ADNLPProblems.$(prob)(use_nls = true)"))
+    if (typeof(nls_prob) <: ADNLPModels.ADNLSModel) # if the nls_flag is not supported we ignore the prob
+      test_in_place_residual(prob, nls_prob)
+    end 
+  end
+
   @testset "Test problems compatibility for $prob" begin
     prob_fn = eval(Meta.parse("PureJuMP.$(prob)"))
     model = prob_fn(n = ndef)