Inconsistent parameter handling for pak/iostore block size / patch padding

UE - CoreTech - IoStore - Apr 14, 2025

Users have trouble overriding the blocksize/patchpaddingalign parameters for UnrealPak from UAT commandlines.There is no easy way to specify these parameters through a buildcookrun, instead they n ...

UPoseAsset::SetBasePoseName() always sets INDEX_NONE

UE - Anim - Runtime - Apr 11, 2025

UPoseAsset::SetBasePoseName() does not correctly set the BasePoseIndex when a valid pose name is provided. Regardless of input, the pose defaults back to ReferencePose. Upon inspection of the implem ...

Nanite TwoSidedSign is backwards

UE - Graphics Features - Nanite - Apr 10, 2025

The value of MaterialExpressionTwoSidedSign is flipped when calculating the Opacity Mask for Nanite meshes. This seems to be a regression in 5.5. ...

[CrashReport][Crash] UnrealEditor-Core!IMemoryReadStream::CopyTo()

UE - Rendering Architecture - Apr 10, 2025

Intermittent crash in virtual texture transcode. Usually mempy from nullptr but also occasionally we see the same callstack with memcpy to random location. ...

Crash when attempting to change the parent of a material instance constant through editor scripting

UE - Rendering Architecture - Materials - Apr 9, 2025

The built-in class "UMaterialEditingLibrary" provides various editor scripting functions related to creating and editing materials and material instances. One of these functions, UMaterialEditingLib ...

CitySample - Level MassCrowd - interactions with SmartObjects/ContextualAnimScene is broken in 5.5

UE - AI - Apr 9, 2025

The 5.5 version of the CitySample project, particularly the MassCrowd scene, was not properly maintained. The previously working functionality of NPCs being able to sit on a bench is now broken. CAS ...

Sampling textures with bias in the path of a custom data pin causes derivative operations when avoidable

UE - Rendering Architecture - Materials - Apr 8, 2025

Materials that make use of the analytical derivatives path to avoid hardware derivatives can still generate derivative operations on texture samples when the shading model has a custom data pin and ...

Network Prediction crash when smoothing service instance data is reallocated out from under FNetworkPredictionStateView

UE - Gameplay - Network Prediction - Apr 4, 2025

Received a report from a licensee using Network Prediction Plugin and Mover.  There is a strong likelihood of a crash occurring when using NPP's smoothing option and spawning new NPP-simulating ins ...

Non-Nanite Instanced Static Mesh Collision not showing in collision view

UE - Simulation - Core - Apr 3, 2025

This issue is the same as [Link Removed], but it causes confusion for developers because only Nanite ISM are rendered correctly since UE5. . ...