Blueprint - Crash when a function takes an event as a parameter

UE - Gameplay - Blueprint - Oct 10, 2016

Looks like maybe we aren't replacing the source delegate function (SignatureFunction) reference on the UDelegateProperty after recompiling the class - the function's owner name has the TRASHCLASS pr ...

FileSystemDerivedDataBackend may output a corrupted access log

UE - Foundation - Core - Derived Data - May 20, 2021

This problem is caused by the AccessLogWriter has not been flushed at the termination. The following workaround flushes the Writer.class FFileSystemDerivedDataBackend : public FDerivedDataBackendInt ...

Hot reload breaks code based struct array used in blueprints

UE - Gameplay - Blueprint - Mar 21, 2016

When an array of a struct, defined in code, is used in a blueprint, preforming a hot reload after making changes to the class with the struct will cause the blueprint nodes relating to the struct be ...

Destructible Mesh component doesn't show in bp viewport until the bp is reopened

UE - Simulation - Physics - Destruction - Jun 10, 2016

Destructible Mesh component doesn't show in bp viewport until the bp is reopened User Description: Mesh dont appears in viewport after add DestructibleComponent and set "Destructible Mesh". After ...

Environment Query System (EQS): EnvQuery runtime template object can be created with a non-unique name, corrupting the EnvQueryManager cache

UE - AI - Aug 5, 2025

On file [Engine\Source\Runtime\AIModule\Private\EnvironmentQuery\EnvQueryManager.cpp:812], function UEnvQueryManager::CreateQueryInstance() uses StaticDuplicateObject() to create a new UEnvQuery* (d ...

PlayerController::PlayDynamicForceFeedback called through code does not fire

UE - Gameplay - Input - Feb 25, 2016

Calling PlayDynamicForceFeedback in code does not affect controller rumble. ...

Custom Time Dilation causes PhAT bodies to hover

UE - Simulation - Physics - Nov 5, 2015

Custom Time Dilation causes PhAT bodies to hover This is not only happening with vehicles like the original bug described. This is also happening with PhAT skeletal meshes that are moving. https:/ ...

Blueprint enum-to-string node returning inconsistent results across platforms

UE - Gameplay - Mar 5, 2020

Converting a C++ enum to a string should be a consistent result, however when running in the editor it returns the display-name value instead of the index value. This prevents C++ UENUMs from being ...

Bindless Textures do not mip stream as expected

UE - Rendering - Architecture - RHI - Jan 29, 2025

Bindless textures do not appear to stream mip levels. This issue is separate from an already reported bindless virtual texture streaming issue. When the editor is freshly launched or when mip level ...

Blueprint actor reference breaks after hot reload

UE - Gameplay - Blueprint - Apr 21, 2016

Reference to a blueprint based on a custom class will break if changes are made to the parent class and a hot reload is performed. Error Displayed added to Callstack section. Workaround: Compiling ...