ConditionalBeginDestroy on ActorComponent does not unregister the component with the world nor cause a warning

UE - CoreTech - May 6, 2025

Calling ConditionalBeginDestroy on an ActorComponent (instead of DestroyComponent) can lead to a crash due to the object not being correctly unregistered. BeginDestroy doesn't unregister tick funct ...

FName no longer equals FName_None when constructed with a trailing underscore and digits in range of 1-9

UE - CoreTech - Apr 15, 2025

When an FName is created with a trailing underscore and any number of digits in the range of 1-9 the trailing digits are used as the internal number value for the FName lookup. This results in the F ...

FJsonObjectConverter::ExportCallback_WriteISO8601Dates allows for writing FDateTime that does not have ticks

UE - CoreTech - Mar 12, 2025

Context: `FJsonObjectConverter` is a built-in UE class that makes it easy to convert JSON objects to and from UStructs, including `FDateTime`, which implements a date and time. Problem: An uniniti ...

Incorrect config property serialization for UStructs used as TMap keys or contained in a TSet with a single value. Diffs taken from default-value of each member type, instead of from default-value of the struct

UE - CoreTech - Nov 18, 2024

Consider a UStruct with some basic type members, each one with a default value specified in the struct. Also consider a TSet or TMap with that struct as keys, used inside a UObject as a UProperty an ...

FStaticMeshCompiler::FinishCompilation stalls when compiling multiple meshes.

UE - CoreTech - Oct 7, 2024

Calling "FStaticMeshCompiler::FinishCompilation" on multiple assets simultaneously can cause a hang. Also tested on //UE5/Release-5.5, CL: 36784631 ...

Incremental GC vs Loading Screens deadlock

UE - CoreTech - Sep 5, 2024

A licensee is reporting that using a loading screen with the incremental garbage collector can result in a dead lock when a loading screen is displayed. The licensee found out that:  -------------- ...

Enabling ZenLoader causes editor crash when undoing Level Instance deletion

UE - CoreTech - Sep 5, 2024

Crash reported through UDN. With ZenLoader enabled, deleting a level instance and triggering Undo causes a crash in  ULandscapeComponent::PostEditUndo() The user has provided an example project th ...

EnumRedirections from a Blueprint enum to a c++ enum does not redirect everything correctly.

UE - CoreTech - Aug 20, 2024

There is an engine bug when using the EnumRedirects feature inside a config file. If we have a Blueprint Enum used in our blueprints, and we want to convert all the Blueprint enum references to a C+ ...

Crash handling: Prevent reports of assertions during shutdown after an assertion

UE - CoreTech - Aug 8, 2024

CriticalErrors in FWindowsErrorOutputDevice::Serialize (and other platforms) run some code after the error is detected rather than immediately terminating the process. Some of this other code is spe ...

FILTER_COMMANDLINE_LOGGING cannot be used without forcing UE_COMMAND_LINE_USES_ALLOW_LIST

UE - CoreTech - Jul 30, 2024

There's two ways to affect the commandline in CommandLine.cpp: FILTER_COMMANDLINE_LOGGING - for filtering certain or all args (if left empty) from the log. UE_COMMAND_LINE_USES_ALLOW_LIST - for on ...