diff --git a/scaletest/loadtestutil/client.go b/scaletest/loadtestutil/client.go
index 797139c6ad..144b990089 100644
--- a/scaletest/loadtestutil/client.go
+++ b/scaletest/loadtestutil/client.go
@@ -41,5 +41,11 @@ func extractHeaderAndInnerTransport(rt http.RoundTripper) (http.Header, *http.Tr
 		maps.Copy(headers, ht.Header)
 		return headers, t, nil
 	}
-	return nil, nil, xerrors.New("round tripper is neither HeaderTransport nor Transport")
+	// unrecognized RoundTripper. Just return a default transport, since we only care about preserving headers.
+	t, ok := http.DefaultTransport.(*http.Transport)
+	if !ok {
+		// unhittable, unless the Go stdlib changes.
+		return nil, nil, xerrors.New("DefaultTransport is not *http.Transport")
+	}
+	return make(http.Header), t, nil
 }
diff --git a/scaletest/loadtestutil/client_test.go b/scaletest/loadtestutil/client_test.go
index e1379d33ea..0372e9fc2b 100644
--- a/scaletest/loadtestutil/client_test.go
+++ b/scaletest/loadtestutil/client_test.go
@@ -20,6 +20,7 @@ func TestDupClientCopyingHeaders(t *testing.T) {
 				Header: map[string][]string{
 					"X-Coder-Test":  {"foo"},
 					"X-Coder-Test3": {"socks"},
+					"X-Coder-Test5": {"ninjas"},
 				},
 			},
 			Header: map[string][]string{
@@ -46,5 +47,6 @@ func TestDupClientCopyingHeaders(t *testing.T) {
 	require.Equal(t, "baz", ht.Header.Get("X-Coder-Test2"))
 	require.Equal(t, "clocks", ht.Header.Get("X-Coder-Test3"))
 	require.Equal(t, "bears", ht.Header.Get("X-Coder-Test4"))
+	require.Equal(t, "ninjas", ht.Header.Get("X-Coder-Test5"))
 	require.NotEqual(t, http.DefaultTransport, ht.Transport)
 }