Unreal Engine Issues
Unreal Engine Issues
Client and server can both get stuck waiting for packet sequence history flush
UE - Networking - Sep 4, 2025The issue occurs when both instances have a significant difference between their last sent and last ack'd sequence number, as they will begin waiting for the sequence history to be flushed for a pac ...
FObjectReferenceCache's ResolveObjectReferenceHandleInternal can return pointers to garbage objects
UE - Networking - Aug 6, 2025A FindObjectFast call may return a pointer to an object marked as garbage. The use of that function in FObjectReferenceCache::ResolveObjectReferenceHandleInternal as well as FNetGUIDCache::GetObject ...
IsLocalController returning incorrect value when PIE listen server travels back to standalone map
UE - Networking - Jun 11, 2025In this situation where the listen server travels back to a level without listening, IsLocalController can return the incorrect value. After the NetDriver has been shutdown and destroyed, the pawn a ...
Actor Channel failure occurs when quickly unloading and loading a streaming level
UE - Networking - May 8, 2025With high enough latency, quickly unloading an reloading a streaming level with a replicated actor on the server can cause the actor channel on the client to fail to find this actor: UActorChannel:: ...
Assertion failed in FNetGUIDCache::CleanReferences during seamless travel after reloading primary asset package
UE - Networking - May 7, 2025Following this sequence of events, the ObjectLookup and NetGUIDLookup on the server's PackageMapClient will end up in a bad state. In the ObjectLookup Map, the primary asset's package will be mapped ...
Fatal error when creating listen server on an instance with a PendingNetGame
UE - Networking - Apr 28, 2025This seems to occur because the PendingNetGame is not destroyed when the instance browses to the new level to start listening. In UEngine::LoadMap, UWorld::SetGameMode will create the game mode, pro ...
FFastArraySerializer::DeltaFlags may be saved to blueprint CDO, causing delta struct serialization to be skipped
UE - Networking - Mar 28, 2025When an actor's replicator is first created and initialized, FObjectReplicator::InitWithObject will use the archetype as the source object for copying the properties. From there, the custom delta pr ...
COND_InitialOnly property not written to first replay checkpoint after being changed
UE - Networking - Feb 5, 2025When recording a checkpoint, it is treated as an initial replication, as all the changed properties since the channel was opened need to be recorded. This normally results in any initial only proper ...
Check hit when setting push-model array from a different actor's blueprint
UE - Networking - Jan 31, 2025This is due to the same reason behind [Link Removed], as the stack object is passed to MARK_PROPERTY_DIRTY rather than the array property's owner. ...
UEditorEngine::AddPendingLateJoinClient checks original PIE/SIE state, not current state
UE - Networking - Jan 27, 2025When adding late joining clients, the engine checks the originally requested EPlaySessionWorldType, rather than checking whether or not the session is currently simulating or not. This means if the ...