Unreal Engine Issues

Delta struct serialized fast arrays replicating new elements with no changelist

There is a scenario where delta struct serialized fast arrays can replicate changes that introduce additional elements to the array, but without changelists containing the new data. This needs furt ...

Alt-tabbing out of a Standalone App or packaged version of a game does not trigger LostFocus or ReceiveFocus

If a user uses Alt-tab to change to another window, the ReceivedFocus and LostFocus functions are not called as they would usually be called when using something such as Shift+F1 or Ctrl+Esc. Note: ...

Certain UPROPERTY values are not updated during auto-recompile

Sometimes manual recompile is required to make a blueprint actually recompile data-only changes, but not always. If the last manual compile was with default values, then changes are not updated. If ...

Deploying from Windows to Linux fails on the first attempt

After hitting this failure, if you try to deploy again, then it will work. This only occurs on the first attempt. Initially, I thought I hit a disc space issue I was hitting due to having a sample ...

Actor ClassID Value Read From Data Table only in PIE

When accessing a data table in BP and getting an Actor Class from it the Class will return NULL when in Standalone Game, Launching, or in a packaged game. This only seems to work in PIE. ...

Draw as border is completely opaque when size in negative

When an image widget is set to draw as border it will no longer render as a border if the size is negative. The widget appears completely opaque. ...

GetAllMobileRelevantLayerNames drops those layers which are only connected to RuntimeVirtualTextureOutput Node

in UMaterial::GetAllReferencedExpressions, the mobile branch ignores every CustomOutputExpressions including RuntimeVirtualTextureOutput. ...

Ensure after reparenting Blueprint and moving a property to the new parent

Moving a property from a recently reparented BP to its new parent will assert in  FBlueprintCompileReinstancer::MoveDependentSkelToReinst at  ensure(PrevStructSize == NewStructSize) This only see ...

A niagara emitter with an empty renderer module does not return a position in the package

Unreal Editor can get in an infinite while loop when checking the History of an asset under Perforce.

Unreal Editor can get in an infinite while loop when the action Asset->Source Control->History is used in a Blueprint Asset. Reportedly, this issue is only encountered when using the Branches featur ...