diff --git a/apps/emqx/src/emqx_session.erl b/apps/emqx/src/emqx_session.erl
index 0dd116347..e32ebc610 100644
--- a/apps/emqx/src/emqx_session.erl
+++ b/apps/emqx/src/emqx_session.erl
@@ -818,7 +818,7 @@ redispatch_shared_messages(#session{inflight = Inflight}) ->
             %% Only QoS1 messages get redispatched, because QoS2 messages
             %% must be sent to the same client, once they're in flight
             ({_, #inflight_data{message = #message{qos = ?QOS_2} = Msg}}) ->
-                ?SLOG(warning, "Not redispatching qos2 msg: ~s", [Msg]);
+                ?SLOG(warning, "Not redispatching qos2 msg: ~p", [Msg]);
             ({_, #inflight_data{message = #message{topic = Topic, qos = ?QOS_1} = Msg}}) ->
                 case emqx_shared_sub:get_group(Msg) of
                     {ok, Group} ->
diff --git a/apps/emqx/src/emqx_shared_sub.erl b/apps/emqx/src/emqx_shared_sub.erl
index 22866bb3d..5163554a7 100644
--- a/apps/emqx/src/emqx_shared_sub.erl
+++ b/apps/emqx/src/emqx_shared_sub.erl
@@ -225,7 +225,7 @@ get_group(Msg) ->
     end.
 
 %% @doc Negative ack dropped message due to inflight window or message queue being full.
--spec maybe_nack_dropped(emqx_types:message()) -> ok.
+-spec maybe_nack_dropped(emqx_types:message()) -> boolean().
 maybe_nack_dropped(Msg) ->
     case get_group_ack(Msg) of
         ?NO_ACK -> false;