diff --git a/src/emqx_channel.erl b/src/emqx_channel.erl
index 791433b37..daaec16e1 100644
--- a/src/emqx_channel.erl
+++ b/src/emqx_channel.erl
@@ -56,9 +56,12 @@
         , clear_keepalive/1
         ]).
 
-%% Exports for CT
 -export([set_field/3]).
 
+-ifdef(TEST).
+-export([ensure_timer/3]).
+-endif.
+
 -import(emqx_misc,
         [ run_fold/3
         , pipeline/3
@@ -622,20 +625,20 @@ do_publish(PacketId, Msg = #message{qos = ?QOS_1}, Channel) ->
     NChannel = ensure_quota(PubRes, Channel),
     handle_out(puback, {PacketId, RC}, NChannel);
 
-do_publish(PacketId, Msg = #message{qos = ?QOS_2},
-           Channel = #channel{session = Session}) ->
+do_publish(PacketId, Msg = #message{qos = ?QOS_2}, Channel0) ->
+    #channel{session = Session} = NChannel = maybe_clean_expired_awaiting_rel(Channel0),
     case emqx_session:publish(PacketId, Msg, Session) of
         {ok, PubRes, NSession} ->
             RC = puback_reason_code(PubRes),
-            NChannel1 = ensure_timer(await_timer, Channel#channel{session = NSession}),
+            NChannel1 = ensure_timer(await_timer, NChannel#channel{session = NSession}),
             NChannel2 = ensure_quota(PubRes, NChannel1),
             handle_out(pubrec, {PacketId, RC}, NChannel2);
         {error, RC = ?RC_PACKET_IDENTIFIER_IN_USE} ->
             ok = emqx_metrics:inc('packets.publish.inuse'),
-            handle_out(pubrec, {PacketId, RC}, Channel);
+            handle_out(pubrec, {PacketId, RC}, NChannel);
         {error, RC = ?RC_RECEIVE_MAXIMUM_EXCEEDED} ->
             ok = emqx_metrics:inc('packets.publish.dropped'),
-            handle_out(disconnect, RC, Channel)
+            handle_out(disconnect, RC, NChannel)
     end.
 
 ensure_quota(_, Channel = #channel{quota = undefined}) ->
@@ -841,7 +844,6 @@ handle_out(connack, {?RC_SUCCESS, SP, Props}, Channel = #channel{conninfo = Conn
                           [ConnInfo, emqx_reason_codes:name(?RC_SUCCESS)],
                           AckProps
                          ),
-
     return_connack(?CONNACK_PACKET(?RC_SUCCESS, SP, NAckProps),
                    ensure_keepalive(NAckProps, Channel));
 
@@ -923,7 +925,7 @@ return_connack(AckPacket, Channel) ->
                                       },
             {Packets, NChannel1} = do_deliver(Publishes, NChannel),
             Outgoing = [{outgoing, Packets} || length(Packets) > 0],
-            {ok, Replies ++ Outgoing, NChannel1}
+            {ok, Replies ++ Outgoing, ensure_timer(retry_timer, NChannel1)}
     end.
 
 %%--------------------------------------------------------------------
@@ -1127,17 +1129,8 @@ handle_timeout(_TRef, retry_delivery,
             handle_out(publish, Publishes, reset_timer(retry_timer, Timeout, NChannel))
     end;
 
-handle_timeout(_TRef, expire_awaiting_rel,
-               Channel = #channel{conn_state = disconnected}) ->
-    {ok, Channel};
-handle_timeout(_TRef, expire_awaiting_rel,
-               Channel = #channel{session = Session}) ->
-    case emqx_session:expire(awaiting_rel, Session) of
-        {ok, NSession} ->
-            {ok, clean_timer(await_timer, Channel#channel{session = NSession})};
-        {ok, Timeout, NSession} ->
-            {ok, reset_timer(await_timer, Timeout, Channel#channel{session = NSession})}
-    end;
+handle_timeout(_TRef, expire_awaiting_rel, Channel) ->
+    {ok, clean_expired_awaiting_rel(Channel)};
 
 handle_timeout(_TRef, expire_session, Channel) ->
     shutdown(expired, Channel);
@@ -1182,6 +1175,26 @@ reset_timer(Name, Time, Channel) ->
 clean_timer(Name, Channel = #channel{timers = Timers}) ->
     Channel#channel{timers = maps:remove(Name, Timers)}.
 
+is_timer_alive(Name, #channel{timers = Timers}) ->
+    case maps:find(Name, Timers) of
+        error -> false;
+        {ok, _TRef} -> true
+    end.
+
+maybe_clean_expired_awaiting_rel(Channel) ->
+    case is_timer_alive(await_timer, Channel) of
+        true -> Channel;
+        false -> clean_expired_awaiting_rel(Channel)
+    end.
+
+clean_expired_awaiting_rel(Channel = #channel{session = Session}) ->
+    case emqx_session:expire(awaiting_rel, Session) of
+        {ok, NSession} ->
+            clean_timer(await_timer, Channel#channel{session = NSession});
+        {ok, Timeout, NSession} ->
+            reset_timer(await_timer, Timeout, Channel#channel{session = NSession})
+    end.
+
 -spec interval(channel_timer(), channel()) -> timeout().
 interval(alive_timer, #channel{keepalive = KeepAlive}) ->
     emqx_keepalive:info(interval, KeepAlive);
@@ -1878,10 +1891,6 @@ is_disconnect_event_enabled(discarded) ->
 is_disconnect_event_enabled(takeovered) ->
     emqx:get_env(client_disconnect_takeovered, false).
 
-%%--------------------------------------------------------------------
-%% For CT tests
-%%--------------------------------------------------------------------
-
 set_field(Name, Value, Channel) ->
     Pos = emqx_misc:index_of(Name, record_info(fields, channel)),
     setelement(Pos+1, Channel, Value).