Crash when destroying a geometry collection actor

UE - Simulation - Physics - Aug 7, 2020

When an actor with geometry collection is destroyed, the engine doesn't remove elements from array in the ChaosSolver So illegal references occurs. Removing element with following quick fix code ...

Float Curve evaluation may yield completely wrong results due to floating-point precision issue

UE - Anim - Runtime - Oct 31, 2024

Note: This is possibly related to [Link Removed]. For some inputs, function UE::Curves::WeightedEvalForTwoKeys() inside file "CurveEvaluation.cpp" can incorrectly return the value of the first key, ...

Changes to Instanced Properties default value on BP not propagated to placed actors in the opened level

UE - Foundation - May 15, 2025

In UE versions 5.4 and onwards (as of CL 42589677 in Main), when an Instanced UObject property is defined in an Actor Blueprint, modifying the default value in the Blueprint does not propagate the c ...

Blueprints from UE4 with dangling delegate reroute node crashes on UE5 load

UE - Gameplay - Blueprint Compiler - Dec 22, 2023

If a project from UE 4.27 or earlier has a blueprint with a reroute node dangling (no outgoing connection) from a Custom Event Node's delegate pin (red), this blueprint will crash when loaded in UE ...

Some materials render black on Iphone 6 series phones

UE - Platform - Mobile - Oct 6, 2016

Some materials are not rendering on iphone 6 series devices. They will render completely black on one device but not others in the same series. Replacing the material with a basic material renders o ...

Large Landscapes cause long PIE start time delays

UE - LD & Modeling - Terrain - Landscape - Jan 29, 2020

These delays appear with large Landscapes (for example 8029 x 8029) . The delays only start occurring after the level is saved and reopened. After which PIE start times will be 5 to 15 times longer ...

Crash on Assigning Material to Element 1 in Reimported Static Mesh

Tools - May 15, 2015

[Link Removed] When you reimport a Static Mesh with an Added Material ID associated with it and in the Static Mesh Editor assign a material, the engine crashes. Also reproduced in Main Promotable- ...

WP level instance runtime settings affect streaming generation

UE - World Creation - Worldbuilding Tools - World Partition - Nov 16, 2023

If a level instance uses different runtime settings then it can override the main WP's runtime settings with UWorldPartitionRuntimeSpatialHash::ApplyCVars Runtime settings:GRuntimeSpatialHashUseA ...

Reference to control rig can be lost on actors with multiple skeletal mesh components

UE - Anim - Rigging - Control Rig - Apr 4, 2023

In the attached project, when we initially add a control rig track for the actor with multiple skeletal mesh components, we add the control rig for the correct component because FControlRigParameter ...