Unreal Engine Issues

Iris - Fast Array ItemMap is empty in PostReplicatedAdd

With Iris enabled, the ItemMap is populated correctly only on the next frame, but it is empty during the callback. This differs from the behavior of the current system, where the ItemMap is populat ...

InverseExposureLerp should return 1.0 when EYE_ADAPTION_DISABLED is 1

Materials using EyeAdaptationInverse may render incorrectly when debug visualizations are active.   This issue can be resolved by modifying the EyeAdaptionInverse function in EyeAdaptionCommon.us ...

Crash in NaniteStreamManager when Nanite data fails to decode corrupt data from DDC

If Nanite data becomes corrupt in the DDC, the Editor may crash in FStreamingManager::InstallReadyPages() when the Pending.State is FPendingPage::EState::DDC_Ready but the resulting SrcPtr is null b ...

Default subobject of dynamic component skips initial replication

Because the component's subobjects are replicated before the component, the content block for the subobject is received before the component has been created on the client. Since this subobject is c ...

Partially loaded level instance becomes fully loaded after editing nested level instance

Affect Indirect Lighting While Hidden can affect the environment after data layer unload in editor

After setting Affects Indirect Lighting While Hidden but before saving the level, the emissive contribution persistents through datalayer visibility toggles. This does not appear to occur in PIE, on ...

During SIE (simulate) and ejected-PIE, modifying a map actor causes triggers RerunConstructionScript() which discards all runtime modifications to SCS components

When Simulating, or Playing-In-Editor and ejected, modifying an actor in the editor world causes the SIE/PIE runtime actor to recreate its blueprint added components via AActor::RerunConstructionScr ...

Incremental GC vs Loading Screens deadlock

A licensee is reporting that using a loading screen with the incremental garbage collector can result in a dead lock when a loading screen is displayed. The licensee found out that:  -------------- ...

MVVM: Bindings set to Tick aren't executed every frame

FDateRange cannot be declared as UPROPERTY

Unlike other range wrapper structs, such as FFloatRange, marking a FDateRange as a UPROPERTY results in the following error: error : Unable to find 'class', 'delegate', 'enum', or 'struct' with nam ...