diff --git a/core/config/config.hpp b/core/config/config.hpp
index a0ffefcf9f8..1fafa5e80d8 100644
--- a/core/config/config.hpp
+++ b/core/config/config.hpp
@@ -86,14 +86,16 @@ inline std::shared_ptr<T> get_pointer(const pnode& config,
 
 
 template <typename T>
-inline deferred_factory_parameter<std::remove_const_t<T>> get_factory(
-    const pnode& config, const registry& context, type_descriptor td);
+inline deferred_factory_parameter<T> get_factory(const pnode& config,
+                                                 const registry& context,
+                                                 type_descriptor td);
 
 template <>
-inline deferred_factory_parameter<LinOpFactory> get_factory<const LinOpFactory>(
-    const pnode& config, const registry& context, type_descriptor td)
+inline deferred_factory_parameter<const LinOpFactory>
+get_factory<const LinOpFactory>(const pnode& config, const registry& context,
+                                type_descriptor td)
 {
-    deferred_factory_parameter<LinOpFactory> ptr;
+    deferred_factory_parameter<const LinOpFactory> ptr;
     if (config.is(pnode::status_t::data)) {
         ptr = context.search_data<LinOpFactory>(config.get_data<std::string>());
     } else if (config.is(pnode::status_t::map)) {
@@ -105,18 +107,17 @@ inline deferred_factory_parameter<LinOpFactory> get_factory<const LinOpFactory>(
 }
 
 template <>
-deferred_factory_parameter<stop::CriterionFactory>
+deferred_factory_parameter<const stop::CriterionFactory>
 get_factory<const stop::CriterionFactory>(const pnode& config,
                                           const registry& context,
                                           type_descriptor td);
 
 
 template <typename T>
-inline std::vector<deferred_factory_parameter<std::remove_const_t<T>>>
-get_factory_vector(const pnode& config, const registry& context,
-                   type_descriptor td)
+inline std::vector<deferred_factory_parameter<T>> get_factory_vector(
+    const pnode& config, const registry& context, type_descriptor td)
 {
-    std::vector<deferred_factory_parameter<std::remove_const_t<T>>> res;
+    std::vector<deferred_factory_parameter<T>> res;
     // for loop in config
     if (config.is(pnode::status_t::array)) {
         for (const auto& it : config.get_array()) {
diff --git a/core/config/stop_config.cpp b/core/config/stop_config.cpp
index 4fa20ea1ba2..7ae52b8da8d 100644
--- a/core/config/stop_config.cpp
+++ b/core/config/stop_config.cpp
@@ -137,12 +137,12 @@ configure_implicit_residual(const pnode& config, const registry& context,
 
 
 template <>
-deferred_factory_parameter<stop::CriterionFactory>
+deferred_factory_parameter<const stop::CriterionFactory>
 get_factory<const stop::CriterionFactory>(const pnode& config,
                                           const registry& context,
                                           type_descriptor td)
 {
-    deferred_factory_parameter<stop::CriterionFactory> ptr;
+    deferred_factory_parameter<const stop::CriterionFactory> ptr;
     if (config.is(pnode::status_t::data)) {
         return context.search_data<stop::CriterionFactory>(
             config.get_data<std::string>());
diff --git a/core/test/config/config.cpp b/core/test/config/config.cpp
index b137b220f3f..064d93d216e 100644
--- a/core/test/config/config.cpp
+++ b/core/test/config/config.cpp
@@ -102,9 +102,9 @@ TEST_F(Config, GenerateObjectWithData)
              {"criteria", this->stop_config}}};
     auto obj = build_from_config<0>(p, reg, {"float", ""}).on(this->exec);
 
-    ASSERT_NE(dynamic_cast<const gko::solver::Cg<float>::Factory*>(obj.get()),
+    ASSERT_NE(dynamic_cast<gko::solver::Cg<float>::Factory*>(obj.get()),
               nullptr);
-    ASSERT_NE(dynamic_cast<const gko::solver::Cg<float>::Factory*>(obj.get())
+    ASSERT_NE(dynamic_cast<gko::solver::Cg<float>::Factory*>(obj.get())
                   ->get_parameters()
                   .generated_preconditioner,
               nullptr);
@@ -121,9 +121,9 @@ TEST_F(Config, GenerateObjectWithPreconditioner)
         pnode{{{"Type", pnode{"Cg"}}, {"criteria", this->stop_config}}};
     auto obj = build_from_config<0>(p, reg).on(this->exec);
 
-    ASSERT_NE(dynamic_cast<const gko::solver::Cg<double>::Factory*>(obj.get()),
+    ASSERT_NE(dynamic_cast<gko::solver::Cg<double>::Factory*>(obj.get()),
               nullptr);
-    ASSERT_NE(dynamic_cast<const gko::solver::Cg<double>::Factory*>(obj.get())
+    ASSERT_NE(dynamic_cast<gko::solver::Cg<double>::Factory*>(obj.get())
                   ->get_parameters()
                   .preconditioner,
               nullptr);
@@ -146,14 +146,13 @@ TEST_F(Config, GenerateObjectWithCustomBuild)
         pnode{std::map<std::string, pnode>{{"Type", pnode{"Custom"}}}};
     auto obj = build_from_config<0>(p, reg, {"double", ""}).on(this->exec);
 
-    ASSERT_NE(dynamic_cast<const gko::solver::Cg<double>::Factory*>(obj.get()),
+    ASSERT_NE(dynamic_cast<gko::solver::Cg<double>::Factory*>(obj.get()),
+              nullptr);
+    ASSERT_NE(dynamic_cast<const gko::solver::Bicg<double>::Factory*>(
+                  dynamic_cast<gko::solver::Cg<double>::Factory*>(obj.get())
+                      ->get_parameters()
+                      .preconditioner.get()),
               nullptr);
-    ASSERT_NE(
-        dynamic_cast<const gko::solver::Bicg<double>::Factory*>(
-            dynamic_cast<const gko::solver::Cg<double>::Factory*>(obj.get())
-                ->get_parameters()
-                .preconditioner.get()),
-        nullptr);
 }