diff --git a/proxy/shadowsocks_2022/packet.go b/proxy/shadowsocks_2022/packet.go
index 76f713f30..ebe6d1338 100644
--- a/proxy/shadowsocks_2022/packet.go
+++ b/proxy/shadowsocks_2022/packet.go
@@ -397,16 +397,10 @@ type serverSessionState struct {
 }
 
 func (st *serverSessionState) check(packetID uint64) bool {
-	if st.window == nil {
-		st.window = new(SlidingWindow)
-	}
 	return st.window.Check(packetID)
 }
 
 func (st *serverSessionState) add(packetID uint64) {
-	if st.window == nil {
-		st.window = new(SlidingWindow)
-	}
 	st.window.Add(packetID)
 }
 
@@ -479,6 +473,7 @@ func (s *ClientUDPSession) getServerSession(sessionID uint64, now int64) (*serve
 
 	newState := &serverSessionState{
 		sessionID: sessionID,
+		window:    new(SlidingWindow),
 		cipher:    bodyAead,
 	}
 	newState.lastSeen.Store(now)
diff --git a/proxy/shadowsocks_2022/replay.go b/proxy/shadowsocks_2022/replay.go
index 45ffb227a..13beb86e4 100644
--- a/proxy/shadowsocks_2022/replay.go
+++ b/proxy/shadowsocks_2022/replay.go
@@ -100,21 +100,12 @@ type ServerUDPSession struct {
 func (s *ServerUDPSession) CheckPacketID(packetID uint64) bool {
 	s.Lock()
 	defer s.Unlock()
-	if s.Window == nil {
-		s.Window = new(SlidingWindow)
-	}
 	return s.Window.Check(packetID)
 }
 
-// CommitPacketID records a packet ID after the packet has been fully validated.
-// It re-checks the window under the lock, so when the same packet is validated
-// concurrently (e.g. by the workers of two client source addresses), only one is accepted.
 func (s *ServerUDPSession) CommitPacketID(packetID uint64) bool {
 	s.Lock()
 	defer s.Unlock()
-	if s.Window == nil {
-		s.Window = new(SlidingWindow)
-	}
 	return s.Window.CheckAndAdd(packetID)
 }
 
@@ -127,9 +118,6 @@ func (s *ServerUDPSession) getClientBodyCipher() cipher.AEAD {
 func (s *ServerUDPSession) commitClientPacket(packetID uint64, bodyAead cipher.AEAD) bool {
 	s.Lock()
 	defer s.Unlock()
-	if s.Window == nil {
-		s.Window = new(SlidingWindow)
-	}
 	if !s.Window.CheckAndAdd(packetID) {
 		return false
 	}
@@ -161,6 +149,7 @@ func (m *UDPSessionManager) GetOrCreate(sessionID uint64) *ServerUDPSession {
 
 	s := &ServerUDPSession{
 		SessionID: sessionID,
+		Window:    new(SlidingWindow),
 		manager:   m,
 	}
 	s.LastActive.Store(now)
diff --git a/proxy/shadowsocks_2022/shadowsocks_2022.go b/proxy/shadowsocks_2022/shadowsocks_2022.go
index 25c894f9d..28d8b88c1 100644
--- a/proxy/shadowsocks_2022/shadowsocks_2022.go
+++ b/proxy/shadowsocks_2022/shadowsocks_2022.go
@@ -63,9 +63,8 @@ func (s *ServerUDPSession) EnsureLink(
 
 	s.currentConn.Store(conn)
 
-	// The session is routed by client session ID and may outlive the inbound
-	// connection of the source address it started from (SIP022 §3.2.4), so its
-	// lifetime is governed by its own timer rather than by that connection.
+	// UDP Session might travel across multiple connections
+	// don't bind its lifetime to a parent context
 	sessCtx, cancel := context.WithCancel(context.WithoutCancel(ctx))
 	inbound := session.InboundFromContext(sessCtx)
 	if inbound != nil && s.User != nil {