The AABBTree spatial acceleration structure goes off-sync when physics substepping is enabled in a "low" framerate environment.

UE - Simulation - Physics - Mar 15, 2024

When you enable the physics substepping, if you run the console command p.Chaos.Solver.DebugDrawSpatialAccelerationStructure 1, you can see how does not follow the physical object. The user that rep ...

NPC - Instances does not get updates from changes to the parent Niagara Parameter Collection in the editor

UE - Niagara - Oct 4, 2024

When an Niagara Parameter Collection (NPC) is selected as the parent Collection for an NPC Instance (NPCI), all of its current parameters are carried over to the NPCI with their current values as th ...

Crash when attempting to change the parent of a material instance constant through editor scripting

UE - Rendering Architecture - Materials - Apr 9, 2025

The built-in class "UMaterialEditingLibrary" provides various editor scripting functions related to creating and editing materials and material instances. One of these functions, UMaterialEditingLib ...

Using the end of the curve as a weighted tangent does not yield the expected value.

UE - Anim - Runtime - Oct 16, 2023

When changing the tangent value, the last value is sometimes not 1.0 [Reproduce sample project] [Link Removed] ...

Crash when exposing a TOptional<FName> or TOptional<FText> to the editor through a UProperty.

UE - Editor - Workflow Systems - Mar 25, 2025

Support for editor-exposed uproperties of type TOptional<T> has been added by CL 28199740 on september 2023. However, since then until today in UE 5.5, a crash can happen when exposing TOptional<FNa ...

Buoyancy is broken in UE5: even BP with Cube SM component (mass is 1kg) and default Buoyancy Component with one default Pontoon falls on bottom of lake

UE - Simulation - Physics - Jul 26, 2021

Shorter steps:Steps 1-8 from Steps to reproduce (create level with water body)Find BP_BuoyancyExample in Content Browser (Engine>Plugins>Water Content>Blueprints)Place BP_BuoyancyExample above the w ...

[Stream Cache][Assert] - UnrealEditor_Engine!FCachedAudioStreamingManager::RemoveReferenceToChunk() [AudioStreamingCache.cpp:701]

UE - Audio - Stream Caching - Mar 12, 2024

Found while messing around with a revamp of some of the Audio Stream cache tests. The map in this test is a WIP as I'm still just trying stuff out, but hit this assert 5/5 times.Assertion failed: Fo ...

Crash in RHICommandContext& GetContext() in Test/Shipping builds when bUseChecksInShipping is true

UE - Rendering Architecture - RHI - Nov 29, 2022

RHIinit() calls GRHICommandList.GetImmediateCommandList().GetContext() to make sure that GDynamicRHI->Init() initialized the immediate command list (by calling FRHICommandListImmediate::InitializeIm ...

Behavior Tree (BT) services added to root nodes call the initial tick twice

UE - AI - Nov 20, 2024

Behavior Tree (BT) services added to root nodes call the initial tick twice A BT Service with the setting "Call Tick on Search Start" enabled will execute the initial tick twice when added to the ro ...

Available network bandwidth is too low for uncapped but slow frame rates

UE - Networking - Sep 24, 2020

The networking system has a max frame rate of 120hz by default. Inside UNetConnection::Tick it computes an estimated bandwidth by using that max frame rate, the engine's max frame rate, and the actu ...