Niagara - When Interpolated Spawning is disabled, the first frame of each particle unexpectedly does not take into account the Particle Update stage

UE - Niagara - Feb 28, 2025

Foreword: Even if the behavior described here is by design, it is rarely (if ever) expected or desired. This was discussed and agreed to be treated as a bug. Explanation below. When interpolated sp ...

Modifying Notify Properties no longer updates the NotifyName in Blueprints with custom GetNotifyName function.

UE - Anim - Gameplay - Feb 13, 2025

If after placing a notify on an anim sequence timeline you modify a property that is used in the GetNotifyName function of a blueprint notify in engine version previous to 5.5 (5.4.3 for example) th ...

When using 'r.VT.SplitPhysicalPoolSize 64' with nanite meshes, mesh painting does not update in real time (only updates after stroke finished), duplicates mesh painting across separate instances of a mesh, and sometimes doesn't show up in PIE.

UE - Rendering - Architecture - Mar 3, 2025

When using Mesh Painting on nanite meshes in 5.5 with 'r.VT.SplitPhysicalPoolSize' set to non-zero values (e.g. 16, 64), several issues occur, such as: 1. Painting doesn't update in real time (only ...

Video Texture thumbnail does not update after you change its output track

Media Framework - Mar 2, 2017

When updating a video texture's output track, the player preview and world will update immediately, however the texture's thumbnail will revert to default color: Black. When moused over, the thumbn ...

Can Ever Affect Navigation does not detect updates to collision settings at runtime

UE - AI - Jan 27, 2016

When a mesh has its collision updated during runtime the navigation around the mesh does not update. Workaround: If the mesh is set to simulate physics then updates to its collision will update nav ...

Components defaults not updating on hot reload

UE - Gameplay - Blueprint - Apr 11, 2017

Certain values, when changed in code, are not updated in a hot reload. For example, changing the Target Arm Length of a spring arm component will updated after hot reload, but changing the Scale do ...

Updating a material layer may not update materials that are using that material layer instance

UE - Rendering - Architecture - Materials - Jan 7, 2022

Material layer instances do not generate a valid UMaterialFunctionInterface::StateId. For this reason, materials and material instances that use material layer instances will not recompile their sh ...

Split Struct nodes do not update if the struct variable is changed

UE - Gameplay - Blueprint - Aug 30, 2017

If a struct variable inside a blueprint has its node split, changing the variable form one struct to another does not update the split pin. Recombining / resplitting the struct has no affect. Work ...

WidgetComponent is not updated with occlusion culling disabled

UE - Platform - XR - May 7, 2025

LastRenderTime is never updated with occlusion culling disabled, so the widget component will always stop updating.  (see UWidgetComponent::ShouldDrawWidget) Developers can force updates by TickWhen ...