proxy/build.gradle.kts

@@ -100,6 +100,7 @@ tasks {
     runShadow {
         workingDir = file("run").also(File::mkdirs)
         standardInput = System.`in`
+        jvmArgs("-Dvelocity.packet-decode-logging=true")
     }
     named<JavaExec>("run") {
         workingDir = file("run").also(File::mkdirs)

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientConfigSessionHandler.java

@@ -170,7 +170,11 @@ public class ClientConfigSessionHandler implements MinecraftSessionHandler {
   @Override
   public boolean handle(KnownPacksPacket packet) {
     callConfigurationEvent().thenRun(() -> {
-      player.getConnectionInFlightOrConnectedServer().ensureConnected().write(packet);
+      VelocityServerConnection targetServer =
+          player.getConnectionInFlightOrConnectedServer();
+      if (targetServer != null) {
+        targetServer.ensureConnected().write(packet);
+      }
     }).exceptionally(ex -> {
       logger.error("Error forwarding known packs response to backend:", ex);
       return null;