diff --git a/wireguard.cpp b/wireguard.cpp
index 42346ae..14859a3 100644
--- a/wireguard.cpp
+++ b/wireguard.cpp
@@ -651,6 +651,7 @@ bool WireguardProcessor::IsMainThreadPacket(Packet *packet) {
 // Handles an incoming WireGuard packet from the UDP side, decrypt etc.
 void WireguardProcessor::HandleUdpPacket(Packet *packet, bool overload) {
   uint32 type;
+  assert(packet->protocol != 0xCD && (uint16)packet->addr.sin.sin_family != 0xCDCD); // catch msvc uninit mem
 
   // Unscramble incoming packets
 #if WITH_HEADER_OBFUSCATION
@@ -699,19 +700,6 @@ invalid_size:
   }
 }
 
-void WgPeer::CopyEndpointToPeer_Locked(WgKeypair *keypair, const IpAddr *addr) {
-  // Remember how to send packets to this peer
-  if (keypair->peer->allow_endpoint_change_ &&
-      CompareIpAddr(&keypair->peer->endpoint_, addr) && addr->sin.sin_family != 0) {
-#if WITH_SHORT_HEADERS
-    // When the endpoint changes, forget about using the short key.
-    keypair->broadcast_short_key = 0;
-    keypair->can_use_short_key_for_outgoing = false;
-#endif  // WITH_SHORT_HEADERS
-    keypair->peer->endpoint_ = *addr;
-  }
-}
-
 #if WITH_SHORT_HEADERS
 void WireguardProcessor::HandleShortHeaderFormatPacket(uint32 tag, Packet *packet) {
   assert(dev_.IsMainOrDataThread());
@@ -809,8 +797,6 @@ void WireguardProcessor::HandleShortHeaderFormatPacket(uint32 tag, Packet *packe
 
   keypair->send_ctr_acked = std::max<uint64>(keypair->send_ctr_acked, acked_counter);
 
-  WgPeer::CopyEndpointToPeer_Locked(keypair, &packet->addr);
-
   // Periodically broadcast out the short key 
   if ((tag & WG_SHORT_HEADER_KEY_ID_MASK) == 0x00 && !keypair->did_attempt_remember_ip_port) {
     keypair->did_attempt_remember_ip_port = true;
@@ -848,6 +834,19 @@ void WireguardProcessor::NotifyHandshakeComplete() {
 void WireguardProcessor::HandleAuthenticatedDataPacket_WillUnlock(WgKeypair *keypair, Packet *packet) {
   WgPeer *peer = keypair->peer;
   assert(peer->IsPeerLocked());
+  assert(packet->addr.sin.sin_family != 0);
+
+  // Remember the endpoint of the peer
+  if (peer->allow_endpoint_change_ &&
+      (CompareIpAddr(&peer->endpoint_, &packet->addr) | (peer->endpoint_protocol_ ^ packet->protocol)) != 0) {
+#if WITH_SHORT_HEADERS
+    // When the endpoint changes, forget about using the short key.
+    keypair->broadcast_short_key = 0;
+    keypair->can_use_short_key_for_outgoing = false;
+#endif  // WITH_SHORT_HEADERS
+    peer->endpoint_ = packet->addr;
+    peer->endpoint_protocol_ = packet->protocol;
+  }
 
   // Remember how many incoming packets we've seen so we can approximate loss
   keypair->incoming_packet_count++;
@@ -969,9 +968,6 @@ getout:
     goto getout;
   } else {
     assert(!keypair->peer->marked_for_delete_);
-
-    WgPeer::CopyEndpointToPeer_Locked(keypair, &packet->addr);
-
     HandleAuthenticatedDataPacket_WillUnlock(keypair, packet);
   } 
 }
diff --git a/wireguard_proto.h b/wireguard_proto.h
index ec8afc3..735f017 100644
--- a/wireguard_proto.h
+++ b/wireguard_proto.h
@@ -509,7 +509,6 @@ private:
   void WriteMacToPacket(const uint8 *data, MessageMacs *mac);
   void CheckAndUpdateTimeOfNextKeyEvent(uint64 now);
   static void DeleteKeypair(WgKeypair **kp);
-  static void CopyEndpointToPeer_Locked(WgKeypair *keypair, const IpAddr *addr);
   static void DelayedDelete(void *x);
   size_t WriteHandshakeExtension(uint8 *dst, WgKeypair *keypair);
   void InsertKeypairInPeer_Locked(WgKeypair *keypair);