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 ...

Float Curve evaluation may yield completely wrong results due to floating-point precision issue

UE - Anim - Runtime - Oct 31, 2024

Note: This is possibly related to [Link Removed]. For some inputs, function UE::Curves::WeightedEvalForTwoKeys() inside file "CurveEvaluation.cpp" can incorrectly return the value of the first key, ...

Geometry Collection (GC) fragments are affecting the Navmesh in wrong positions

UE - Simulation - Physics - Destruction - Dec 6, 2024

Geometry Collection (GC) fragments are affecting the Navmesh in wrong positions and the identified cause is wrong indexing. Once a GC breaks, it's fragments, when big enough, are creating islands in ...

Visual Logger Timeline is not updated when Viewport is in fullscreen

UE - AI - Debugging - Jan 14, 2025

Context The Visual Logger is a powerful debugging tool to create and record visual representations, and allows people to review the data. Problem The problem is that it does not record things don ...

Keying Level Sequence Crashes Engine

UE - Anim - Sequencer - Dec 12, 2024

Repro rate 3/5 Regression to be tested Testing with a fresh level sequence no crash occurs, Tried to do it without rekeying and did not get a crash. I repro'd it a few times and sometimes no crash ...

Regression: Several project settings, especially from built-in Plugins, are being silently erased when previously they were not, which is perceived as a bug

UE - Foundation - Feb 28, 2025

In UE's Project Settings, some pages are saved automatically to the project's "Config/Default<CATEGORY>.ini" file (meant to be version-controlled) on every change. Other pages have buttons "Set as D ...

Niagara - When Interpolated Spawning is disabled, the first frame of each particle unexpectedly does not take into account the Particle Update stage

UE - Niagara - Feb 28, 2025

Foreword: Even if the behavior described here is by design, it is rarely (if ever) expected or desired. This was discussed and agreed to be treated as a bug. Explanation below. When interpolated sp ...

Nanite Instanced Static Meshes lost selection outlines in UE5.5

UE - Graphics Features - Nanite - Mar 6, 2025

Nanite ISMs lost selection outlines in UE5.5 Actors having an ISM component which uses a static mesh with nanite do not get a selection outline when selected in the editor. Having Nanite is essentia ...

WindDirectionalSourceComponent.h has a meta edit condition that, by referencing an undefined property (bSimulatePhysics), throws an error

UE - Framework - Apr 15, 2025

WindDirectionalSourceComponent.h has a meta edit condition that, by referencing an undefined class property (bSimulatePhysics), throws an error in the logs: LogEditCondition: Error: EditCondition pa ...