ChaosCacheManager is not reproducing Collision Events the second time you Record and Play

UE - Simulation - Physics - Mar 28, 2025

ChaosCacheManager (CCM) is not reproducing Collision events the second time (and onwards) we record a Geometry Collection (GC) breaking session. Particles set to track Collision Events correctly fol ...

ChaosCacheManager is not reproducing Trailing Events

UE - Simulation - Physics - Mar 28, 2025

ChaosCacheManager (CCM) is not reproducing Trailing Events. Particles set to track Trailing Events correctly follow the position of the trailing event when the Geometry Collection (GC) is physically ...

When adding a MovieSceneObjectPropertyTrack and section via python, the new track is not initialized.

UE - Anim - Sequencer - Mar 28, 2025

When you add a track for an Object property via python, the track does not initialize properly and the widget on the track for choosing a new object does not populate typed. This is even after setti ...

Stalled cook due to PoseSearchDatabase DDC storage/retreival

UE - Anim - Gameplay - Mar 27, 2025

reported via UDN: [Link Removed] ...

Raytraced lights with Source Length > 0 behave incorrectly with Megalights

UE - Graphics Features - Ray Tracing - Mar 26, 2025

When Megalights is enabled, light can leak into areas that should be occluded for lights with smallish (5.0) source length and source size. [Image Removed][Image Removed] This was taken with r.Ray ...

[Iris] DestroyObjectsPendingDestroy not called on server with no clients

UE - Networking - Iris - Mar 25, 2025

In UNetDriver::TickFlush, UReplicationSystem::PreSendUpdate is not called on the server when it does not have any client connections. PreSendUpdate is where DestroyObjectsPendingDestroy is called fr ...

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 ...

Users can't change flags on asset entries in PSD when the asset was added via a Branch In notify

UE - Anim - Gameplay - Mar 19, 2025

Assets added to a PSD via a Branch In notify can't have their flags changed within the database. When the flags (like mirror, disable, etc) are changed, they revert back to the original value when ...

When a Niagara User Parameter is renamed, mesh bindings on Niagara Mesh Renderers are not updated, and the binding is silently broken

UE - Niagara - Mar 13, 2025

In Niagara, Mesh Renderers expose a "Meshes" array for selecting the meshes to be rendered. On each array entry, a property "Mesh Parameter Binding" is available and allows the user to override that ...

Popping Ribbon UVs

UE - Niagara - Mar 10, 2025

Please see the Additional Link for related UDN information. The UV popping described can be subtle, depending on settings; it's affected by spawn rate and GPU vs CPU. The popping shown in the gif t ...