diff --git a/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl b/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
index c8d073a28..6a50c553d 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
@@ -323,7 +323,7 @@ show_resource(#{id := Id}, _Params) ->
     case emqx_rule_registry:find_resource(Id) of
         {ok, R} ->
             Status =
-                lists:flatten(
+                lists:concat(
                   [ case rpc:call(Node, emqx_rule_engine, get_resource_status, [Id]) of
                         {badrpc, _} -> [];
                         {ok, St} -> [maps:put(node, Node, St)];
@@ -575,7 +575,7 @@ sort_by(Pos, TplList) ->
         end, TplList).
 
 get_rule_metrics(Id) ->
-    lists:flatten(
+    lists:concat(
       [ case rpc:call(Node, emqx_rule_metrics, get_rule_metrics, [Id]) of
             {badrpc, _} -> [];
             Res -> [maps:put(node, Node, Res)]
@@ -583,7 +583,7 @@ get_rule_metrics(Id) ->
         || Node <- ekka_mnesia:running_nodes()]).
 
 get_action_metrics(Id) ->
-    lists:flatten(
+    lists:concat(
       [ case rpc:call(Node, emqx_rule_metrics, get_action_metrics, [Id]) of
             {badrpc, _} -> [];
             Res -> [maps:put(node, Node, Res)]
diff --git a/apps/emqx_rule_engine/src/emqx_rule_engine_cli.erl b/apps/emqx_rule_engine/src/emqx_rule_engine_cli.erl
index a58bfc0d1..1284184ca 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine_cli.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine_cli.erl
@@ -273,7 +273,7 @@ format(#resource{id = Id,
                  config = Config,
                  description = Descr}) ->
     Status =
-        lists:flatten(
+        lists:concat(
           [ case rpc:call(Node, emqx_rule_engine, get_resource_status, [Id]) of
                 {badrpc, _} -> [];
                 {ok, St} -> [maps:put(node, Node, St)];
@@ -372,7 +372,7 @@ get_actions() ->
     emqx_rule_registry:get_actions().
 
 get_rule_metrics(Id) ->
-    lists:flatten(
+    lists:concat(
       [ case rpc:call(Node, emqx_rule_metrics, get_rule_metrics, [Id]) of
             {badrpc, _} -> [];
             Res -> [maps:put(node, Node, Res)]
@@ -380,7 +380,7 @@ get_rule_metrics(Id) ->
       || Node <- ekka_mnesia:running_nodes()]).
 
 get_action_metrics(Id) ->
-    lists:flatten(
+    lists:concat(
       [ case rpc:call(Node, emqx_rule_metrics, get_action_metrics, [Id]) of
             {badrpc, _} -> [];
             Res -> [maps:put(node, Node, Res)]