"Scale for <ComponentName> has a component set to zero, which will result in a bad body instance" warning spam when moving actor instance even with Collision Profile overriden to "NoCollision"

UE - Simulation - Core - Jan 12, 2026

When a StaticMeshComponent has a scale component of zero in WorldSpace (after accumulating with the hierarchy from the root to it), function UPrimitiveComponent::OnCreatePhysicsState() logs the warn ...

CommonListView EntryWidgetClass allows invalid assignment via “Use Selected Asset From Content Browser”

UE - Editor - UI Systems - Jan 6, 2026

CommonListView requires its EntryWidgetClass to implement UserObjectListEntry. This requirement is correctly enforced by the Entry Widget Class dropdown, which filters out widgets that only implemen ...

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor

UE - World Creation - Worldbuilding Tools - World Partition - Dec 18, 2025

Changing bIsSpatiallyLoaded can cause an Actor to be duplicated during Play-In-Editor. As described in the steps to reproduce, if we keep swapping bIsSpatiallyLoaded state and save a Streaming Level ...

Paper2D: Editor hangs when assigning Sprite Atlas Group to Sprite

UE - Gameplay - Paper2D - Dec 16, 2025

In UE 5.3 and later, assigning a Sprite Atlas Group to a UPaperSprite asset can cause the editor to hang and eventually crash. This behavior has been reproduced in 5.3, 5.6, and a recent UE5-main so ...

Iris - BeginPlay not called on client for statically placed, low-priority replicated actor

UE - Networking - Iris - Dec 11, 2025

On the client, NotifyBeginPlay is triggered via AGameStateBase::OnRep_ReplicatedHasBegunPlay. However, if a replicated actor is waiting on its initial replicated state to be received and applied (bA ...

Replicated timeline may not call Finished event on client

UE - Networking - Dec 9, 2025

It seems this can happen if the timeline component on the client receives an update from the server for the final position of the timeline, causing it to be set as no longer playing before it has a ...

Drag and Drop fails in Standalone and Packaged builds when WidgetComponent’s Widget is set at runtime

UE - Editor - UI Systems - Dec 4, 2025

When a UWidgetComponent has its widget assigned dynamically at runtime using CreateWidget and SetWidget, drag & drop operations fail in Standalone Game and packaged/game builds, while working correc ...

Custom thumbnails don't get updated until the asset is saved

UE - Editor - Workflow Systems - Dec 4, 2025

This is a regression, here's the repro in FN/Main (48954958) : [Link Removed] And now in UE5.7 (48496583) : [Link Removed] ...

Unreal Engine Fails to Launch with Vulkan SM6 RHI and RenderDoc Auto-Attach Enabled

UE - Rendering - Architecture - RHI - Dec 3, 2025

When launching Unreal Engine with the Vulkan RHI, SM6 and RenderDoc Auto Attach on Startup enabled, the engine fails to initialize with the error: “A compatible Vulkan Driver is required to run the ...

PIE also rendering in-active / unfocused editor viewport

UE - Rendering - Graphics Features - Nov 28, 2025

In 5.8, after entering PIE, the editor will start doing two SceneRenders per frame. This dramatically drops performance. Presumably this second render is for the inactive / unfocused editor viewport ...