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 ...

Fix function forwarding in demo drivers in instant replays

UE - Networking - Jul 13, 2020

Demo drivers that are actively playing back a replay while still connected to another server as a client (via game net driver) will generate warnings due to the function forwarding code (UNetDriver: ...

Naming CustomEvent string Input "DisplayName" breaks Blueprint Node

UE - Gameplay - Blueprint Editor - Jan 4, 2018

Naming a custom event string input DisplayName will cause the BP Node spawner to use blank or user-entered data for node listing+creation. Additional Notes: This also occurs when renaming the Text ...

StaticMeshActors spawned at runtime are not visible until a property has been changed and also have no collision unless set to moveable

UE - Gameplay - Dec 22, 2015

Spawning a StaticMeshActor at runtime results in the StaticMeshActor not being visible until a property has been changed, such as the material for the Static Mesh. The spawned actor will also have n ...

Hot reloading changes to a struct causes data table assets to break

UE - Gameplay - Mar 28, 2017

If a data table asset is based on a custom struct, making changes to and hot reloading the struct will not update the data table in the editor. Restarting the editor will prevent the data table fro ...

Crash in FLandscapeRenderSystem on Mobile

UE - Graphics Tools - Terrain - Landscape - Aug 4, 2021

Similar issues have already been reported here for iOS [https://udn.unrealengine.com/s/question/0D52L00004vJelTSAS/crash-ios-in-flandscaperendersystemcomputesectionperviewparameters] and here [https ...

Selecting Public/Private when created a class forces any classes added after to either be Public/Private as well

Tools - Mar 22, 2016

In the New C++ Class window when naming the project, if Public or Private are selected (next to runtime) all classes created after that point will assume Public/Private with no option to have neithe ...

Crash when adding multiple collision types to a mesh

Tools - Jan 27, 2017

Adding various collision types to a single mesh will cause it to hard crash the editor. No Crash Reporter window will open. Note that this happens with the user's mesh, but I was not able to repro ...

Blueprint PaperTileMap Component not Rendering while in Mobile Preview or Launched on Device

UE - Gameplay - Paper2D - Jun 12, 2015

A blueprint with a PaperTileMap component will not render when played through the 'Mobile Preview' or as a packaged project. If the Tilemap alone is dragged into the viewport it renders fine when p ...

Launch on Nexus 9 fails due to unknown arm64-v8a architecture

UE - Platform - Mobile - Mar 13, 2015

Nexus 9 fails due to unrecognized CPU architecture. Need to add mapping of arm64-v8a to arm64 (UE4 internal architecture for this part) so it will fall back to armv7 for now and in future use 64-bi ...