Directly opening a modified map asset of a streaming sublevel does not always force it to be reloaded (inconsistent with other map open behaviors)

UE - Engine Scaling - Streaming - Feb 10, 2026

When the level currently being edited has unsaved changes and the user opens a new one, the Editor asks if the changes should be saved. If the user answers negatively, the level asset is reverted to ...

Blueprint CDO contains removed component from parent class

UE - Gameplay - Blueprint - Apr 28, 2015

Blueprint CDO contains removed component from parent class. From the AnswerHub post: "It appears that if a component is removed from the C++ class, the CDOs for all of the blueprints remain unchang ...

Physical materials cannot be queried

UE - Rendering - Architecture - Materials - Feb 12, 2015

Physical materials placed on starter content shapes always return as invalid for any trace or collision query. ...

Adding Multiple Scene Components to an Actor Causes Parenting Errors

UE - Gameplay - Components - Jan 5, 2016

Attempting to add multiple instances of a Scene Component that was created in code and contains a component such as a Box Collider causes the Box Colliders of each Scene Component to be parented to ...

Crash on play if a BP uses a ClearInstances node followed by an AddInstance node

UE - Graphics Features - Jul 21, 2017

Crash on play if a BP manipulates a InstancedStaticMeshComponent by using a ClearInstances node followed by an AddInstance node. This is a blocker for the licensee. This is a regression: Working ...

Physics Substepping doesn't have the same effect from 4.15 to 4.16

OLD - Anim - Aug 8, 2017

Physics Substepping doesn't have the same effect from 4.15 to 4.16. In 4.16+ the ponytail in the provided project will have a jitter effect even with substepping enabled. This is a regression: Work ...

[CrashReport] UE4Editor_UMG!TBaseDelegate<FMargin>::operator=() [delegatesignatureimpl.inl:381]

UE - Editor - UI Systems - Aug 29, 2017

This is a longstanding and common UMG crash that has affected more than 200 users since at least the 4.15 release. User DescriptionsI was working in the UI and undid several last changes in quick s ...

Planar Reflections Cause Big Performance Hit In Packaged VR Projects

UE - Platform - XR - Jan 22, 2020

Planar reflections notably lower performance in packaged VR project. Linked is an example project and an example package. [Link Removed]. This was tested on a Vive Pro and Oculus Rift(not Rift S). ...

Cannot access private member MarkPropertyDirtyFromRepIndex error when building a nativized blueprint with a replicated property

UE - Networking - May 14, 2020

The following error occurs when building a project that has a replicated variable with the replication condition set to Skip Owner inside a nativized blueprint.UATHelper: Packaging (Windows (64-bit) ...

"Reference space" when exporting LevelSequences with "Override Instance Data"

zComponent - Archive - May 15, 2024

When exporting a Cinematic Camera as FBX and importing it back, all transforms and Camera view are shifted. This happens when in Level Sequence Actor has the property "Transform Origin Actor" set to ...