Client NullReferenceException in OnReplicateRpc when NetworkTrafficStatistics is enabled

[e-scheer]

This issue is related to the previously reported problem in
#948.

When NetworkTrafficStatistics is enabled, clients can receive replicate messages where sendingClient is null.
In NetworkBehaviour.Prediction.OnReplicateRpc, this results in a client-side NullReferenceException when accessing sendingClient.IsValid.

---

Environment

• Unity: 6.x
• FishNet: 4.6.12+
• Client prediction enabled
• NetworkTrafficStatistics enabled

---

Steps to Reproduce

1. Enable NetworkTrafficStatistics in any FishNet demo scene
2. Enable client prediction
3. Start a server
4. Start a client (ParrelSync / second editor)
5. Trigger predicted movement or replication
6. Observe client-side NullReferenceException

---

Observed Error

sendingClient is null in OnReplicateRpc, causing a NullReferenceException.

---

Expected Behavior

Network traffic statistics should not throw client-side exceptions.

---

Proposed Fix

Guard against a null sendingClient before accessing IsValid:

#if !UNITY_SERVER
if (_networkTrafficStatistics != null)
{
    bool fromServer = sendingClient != null && sendingClient.IsValid;
    _networkTrafficStatistics.AddInboundPacketIdData(
        PacketId.Replicate,
        GetRpcName(PacketId.Replicate, hash.Value),
        reader.Position - readerPositionAfterDebug + Managing.Transporting.TransportManager.PACKETID_LENGTH,
        gameObject,
        asServer: fromServer
    );
}
#endif

---

Notes

• This resolves the client-side NRE
• Behavior is unchanged when sendingClient is valid
• Follow-up to StatisticsManager bandwidth monitor throws nullref on clients #948

[FirstGearGames]

Thanks for the report. This one has already resolved during development; it will be available next release.

…

On Thu, Jan 1, 2026, 3:42 PM e-scheer ***@***.***> wrote: *e-scheer* created an issue (FirstGearGames/FishNet#994) <#994> This issue is related to the previously reported problem in #948 <#948>. When NetworkTrafficStatistics is enabled, clients can receive replicate messages where sendingClient is null. In NetworkBehaviour.Prediction.OnReplicateRpc, this results in a client-side NullReferenceException when accessing sendingClient.IsValid. ------------------------------ *Environment* - Unity: 6.x - FishNet: 4.6.12+ - Client prediction enabled - NetworkTrafficStatistics enabled ------------------------------ *Steps to Reproduce* 1. Enable NetworkTrafficStatistics in any FishNet demo scene 2. Enable client prediction 3. Start a server 4. Start a client (ParrelSync / second editor) 5. Trigger predicted movement or replication 6. Observe client-side NullReferenceException ------------------------------ *Observed Error* sendingClient is null in OnReplicateRpc, causing a NullReferenceException. ------------------------------ *Expected Behavior* Network traffic statistics should not throw client-side exceptions. ------------------------------ *Proposed Fix* Guard against a null sendingClient before accessing IsValid: #if !UNITY_SERVERif (_networkTrafficStatistics != null){ bool fromServer = sendingClient != null && sendingClient.IsValid; _networkTrafficStatistics.AddInboundPacketIdData( PacketId.Replicate, GetRpcName(PacketId.Replicate, hash.Value), reader.Position - readerPositionAfterDebug + Managing.Transporting.TransportManager.PACKETID_LENGTH, gameObject, asServer: fromServer );} #endif ------------------------------ *Notes* - This resolves the client-side NRE - Behavior is unchanged when sendingClient is valid - Follow-up to #948 <#948> — Reply to this email directly, view it on GitHub <#994>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGPJC3VH4AI43AZDNVHZVDD4EWBDZAVCNFSM6AAAAACQPDUJQSVHI2DSMVQWIX3LMV43ASLTON2WKOZTG43TKMJXGEYDGNQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[FirstGearGames]

This instance was resolved but another related one might be present #1000

Closing this issue out given this specific problem has been resolved.