Obscure null reference exception without project context

I get this exception in some condition I can’t fully isolate. Once this throws, it starts throwing every single update/tick. After throwing in play mode, it even starts throwing outside of play mode during layout repaint. There is no reference to any of my own scripts. Can someone from the developers take a look?

NullReferenceException: Object reference not set to an instance of an object
Unity.Netcode.FastBufferWriter.get_Length () (at ./Library/PackageCache/com.unity.netcode.gameobjects@1.4.0/Runtime/Serialization/FastBufferWriter.cs:69)
Unity.Netcode.MessagingSystem.ProcessSendQueues () (at ./Library/PackageCache/com.unity.netcode.gameobjects@1.4.0/Runtime/Messaging/MessagingSystem.cs:786)
Unity.Netcode.NetworkManager.OnNetworkPostLateUpdate () (at ./Library/PackageCache/com.unity.netcode.gameobjects@1.4.0/Runtime/Core/NetworkManager.cs:1488)
Unity.Netcode.NetworkManager.NetworkUpdate (Unity.Netcode.NetworkUpdateStage updateStage) (at ./Library/PackageCache/com.unity.netcode.gameobjects@1.4.0/Runtime/Core/NetworkManager.cs:1381)
Unity.Netcode.NetworkUpdateLoop.RunNetworkUpdateStage (Unity.Netcode.NetworkUpdateStage updateStage) (at ./Library/PackageCache/com.unity.netcode.gameobjects@1.4.0/Runtime/Core/NetworkUpdateLoop.cs:185)
Unity.Netcode.NetworkUpdateLoop+NetworkPostLateUpdate+<>c.<CreateLoopSystem>b__0_0 () (at ./Library/PackageCache/com.unity.netcode.gameobjects@1.4.0/Runtime/Core/NetworkUpdateLoop.cs:268)

Reference from the last stack element: https://github.com/Unity-Technologies/com.unity.netcode.gameobjects/blob/54666c3454a3a5468bca0e1575a0b3059653c64e/com.unity.netcode.gameobjects/Runtime/Serialization/FastBufferWriter.cs#L69

I do not have experience with unsafe code, so I can’t really reverse engineer the problem.

[powersupersport]

@NoelStephensUnity

Since updating to v1.5.1 the issue doesn’t seem to appear anymore. I haven’t done anything too different, so I still can’t confirm what was the exact cause. I’ll make sure to reopen if the issue appears again.

[powersupersport]

Are you able to provide the series of steps you go through to get this issue to happen?

I wish I could. I would’ve honestly tried to solve the problem on my own if it was consistent.

It rarely happens if I connect a client to the server, load a scene, then quickly disconnect them. Though none of that info is very helpful at all.

I am not sure if I can even reproduce the issue in a fresh project, as again, if I could I would’ve probably resolved it.

With all respect, I do not wish to send my entire project to Unity, especially using the bug reporter (sends a lot of unnecessary data about my running processes). If you can’t assist me further that’s totally fine. Thank you for your time.

you might try to update to v1.5.1

I will try doing that and monitor if it fixes it.