diff --git a/apps/emqx/test/emqx_listeners_SUITE.erl b/apps/emqx/test/emqx_listeners_SUITE.erl
index 3dfdf66cf..6ea4d043d 100644
--- a/apps/emqx/test/emqx_listeners_SUITE.erl
+++ b/apps/emqx/test/emqx_listeners_SUITE.erl
@@ -50,7 +50,7 @@ init_per_testcase(Case, Config) when
         Listeners -> emqx_config:put([listeners], maps:remove(quic, Listeners))
     end,
 
-    PrevListeners = emqx_config:get([listeners]),
+    PrevListeners = emqx_config:get([listeners], #{}),
     PureListeners = remove_default_limiter(PrevListeners),
     PureListeners2 = PureListeners#{
         tcp => #{
@@ -72,7 +72,7 @@ init_per_testcase(t_wss_conn, Config) ->
     catch emqx_config_handler:stop(),
     {ok, _} = emqx_config_handler:start_link(),
 
-    PrevListeners = emqx_config:get([listeners]),
+    PrevListeners = emqx_config:get([listeners], #{}),
     PureListeners = remove_default_limiter(PrevListeners),
     PureListeners2 = PureListeners#{
         wss => #{
@@ -97,7 +97,7 @@ init_per_testcase(t_wss_conn, Config) ->
 init_per_testcase(_, Config) ->
     catch emqx_config_handler:stop(),
     {ok, _} = emqx_config_handler:start_link(),
-    PrevListeners = emqx_config:get([listeners]),
+    PrevListeners = emqx_config:get([listeners], #{}),
     PureListeners = remove_default_limiter(PrevListeners),
     emqx_config:put([listeners], PureListeners),
     [
diff --git a/apps/emqx_gateway/src/emqx_gateway_conf.erl b/apps/emqx_gateway/src/emqx_gateway_conf.erl
index 56238d7d5..50fc069fc 100644
--- a/apps/emqx_gateway/src/emqx_gateway_conf.erl
+++ b/apps/emqx_gateway/src/emqx_gateway_conf.erl
@@ -503,9 +503,8 @@ pre_config_update(_, {update_authn, GwName, Conf}, RawConf) ->
     of
         undefined ->
             badres_authn(not_found, GwName);
-        Authn ->
-            NAuthn = maps:merge(Authn, Conf),
-            {ok, emqx_map_lib:deep_put([GwName, ?AUTHN_BIN], RawConf, NAuthn)}
+        _Authn ->
+            {ok, emqx_map_lib:deep_put([GwName, ?AUTHN_BIN], RawConf, Conf)}
     end;
 pre_config_update(_, {update_authn, GwName, {LType, LName}, Conf}, RawConf) ->
     case
@@ -521,10 +520,10 @@ pre_config_update(_, {update_authn, GwName, {LType, LName}, Conf}, RawConf) ->
             case maps:get(?AUTHN_BIN, Listener, undefined) of
                 undefined ->
                     badres_listener_authn(not_found, GwName, LType, LName);
-                Auth ->
+                _Auth ->
                     NListener = maps:put(
                         ?AUTHN_BIN,
-                        maps:merge(Auth, Conf),
+                        Conf,
                         Listener
                     ),
                     {ok,