diff --git a/src/emqx_shared_sub.erl b/src/emqx_shared_sub.erl
index 57c0171ce..db9abe18c 100644
--- a/src/emqx_shared_sub.erl
+++ b/src/emqx_shared_sub.erl
@@ -207,7 +207,7 @@ dispatch_with_ack(SubPid, Group, Topic, Msg, Type) ->
     end.
 
 with_group_ack(Msg, Group, Type, Sender, Ref) ->
-    emqx_message:set_headers(#{shared_dispatch_ack => {Type, Group, Sender, Ref}}, Msg).
+    emqx_message:set_headers(#{shared_dispatch_ack => {Sender, {Type, Group, Ref}}}, Msg).
 
 -spec(without_group_ack(emqx_types:message()) -> emqx_types:message()).
 without_group_ack(Msg) ->
@@ -219,7 +219,7 @@ get_group_ack(Msg) ->
 -spec(get_group(emqx_types:message()) -> {ok, any()} | error).
 get_group(Msg) ->
     case get_group_ack(Msg) of
-        {_Type, Group, _Sender, _Ref} -> {ok, Group};
+        {_Sender, {_Type, Group, _Ref}} -> {ok, Group};
         _ -> error
     end.
 
@@ -230,9 +230,9 @@ is_ack_required(Msg) -> ?NO_ACK =/= get_group_ack(Msg).
 -spec(maybe_nack_dropped(emqx_types:message()) -> boolean()).
 maybe_nack_dropped(Msg) ->
     case get_group_ack(Msg) of
-        ?NO_ACK                        -> false;
-        {fresh, _Group, Sender, Ref}   -> ok == nack(Sender, Ref, dropped);
-        {retry, _Group, _Sender, _Ref} -> maybe_ack(Msg), false;
+        ?NO_ACK                          -> false;
+        {Sender, {fresh, _Group, Ref}}   -> ok == nack(Sender, Ref, dropped);
+        {_Sender, {retry, _Group, _Ref}} -> maybe_ack(Msg), false;
         %% This clause is for backward compatability
         Ack ->
             {Sender, Ref} = fetch_sender_ref(Ack),
@@ -244,7 +244,7 @@ maybe_nack_dropped(Msg) ->
 %% i.e is_ack_required returned true.
 -spec(nack_no_connection(emqx_types:message()) -> ok).
 nack_no_connection(Msg) ->
-    {_Type, _Group, Sender, Ref} = get_group_ack(Msg),
+    {Sender, Ref} = fetch_sender_ref(get_group_ack(Msg)),
     nack(Sender, Ref, no_connection).
 
 -spec(nack(pid(), reference(), dropped | no_connection) -> ok).
@@ -263,9 +263,9 @@ maybe_ack(Msg) ->
             without_group_ack(Msg)
     end.
 
-fetch_sender_ref({_Type, _Group, Sender, Ref}) -> {Sender, Ref};
+fetch_sender_ref({Sender, {_Type, _Group, Ref}}) -> {Sender, Ref};
 %% These clauses are for backward compatability
-fetch_sender_ref({_Group, Sender, Ref}) -> {Sender, Ref};
+fetch_sender_ref({Sender, {_Group, Ref}}) -> {Sender, Ref};
 fetch_sender_ref({Sender, Ref}) -> {Sender, Ref}.
 
 pick(sticky, ClientId, SourceTopic, Group, Topic, FailedSubs) ->
diff --git a/test/emqx_shared_sub_SUITE.erl b/test/emqx_shared_sub_SUITE.erl
index cee53775b..b999657a8 100644
--- a/test/emqx_shared_sub_SUITE.erl
+++ b/test/emqx_shared_sub_SUITE.erl
@@ -48,19 +48,19 @@ t_is_ack_required(_) ->
 
 t_maybe_nack_dropped(_) ->
     ?assertEqual(false, emqx_shared_sub:maybe_nack_dropped(#message{headers = #{}})),
-    Msg = #message{headers = #{shared_dispatch_ack => {fresh, <<"group">>, self(), for_test}}},
+    Msg = #message{headers = #{shared_dispatch_ack => {self(), {fresh, <<"group">>, for_test}}}},
     ?assertEqual(true, emqx_shared_sub:maybe_nack_dropped(Msg)),
     ?assertEqual(ok,receive {for_test, {shared_sub_nack, dropped}} -> ok after 100 -> timeout end).
 
 t_nack_no_connection(_) ->
-    Msg = #message{headers = #{shared_dispatch_ack => {fresh, <<"group">>, self(), for_test}}},
+    Msg = #message{headers = #{shared_dispatch_ack => {self(), {fresh, <<"group">>, for_test}}}},
     ?assertEqual(ok, emqx_shared_sub:nack_no_connection(Msg)),
     ?assertEqual(ok,receive {for_test, {shared_sub_nack, no_connection}} -> ok
                     after 100 -> timeout end).
 
 t_maybe_ack(_) ->
     ?assertEqual(#message{headers = #{}}, emqx_shared_sub:maybe_ack(#message{headers = #{}})),
-    Msg = #message{headers = #{shared_dispatch_ack => {fresh, <<"group">>, self(), for_test}}},
+    Msg = #message{headers = #{shared_dispatch_ack => {self(), {fresh, <<"group">>, for_test}}}},
     ?assertEqual(#message{headers = #{shared_dispatch_ack => ?no_ack}},
                  emqx_shared_sub:maybe_ack(Msg)),
     ?assertEqual(ok,receive {for_test, ?ack} -> ok after 100 -> timeout end).