Unreal Engine Issues
Unreal Engine Issues
FAnimUpdateRateParameters::GetInterpolationAlpha appears to be returning an invalid value for TrailMode
UE - Anim - Aug 5, 2023It appears that FAnimUpdateRateParameters::GetInterpolationAlpha is not returning a sensible value when running in TrailMode. Currently the only variable in the calculation is EvaluationRate which ...
In-Memory replay checkpoints incorrectly deleted when stream length is less than TimeBufferHintSeconds
UE - Networking - Mar 18, 2024The buffer start time is calculated by subtracting the TimeBufferHintSeconds from the stream length: const uint32 BufferStartTimeMS = UE::LWC::FloatToIntCastChecked<uint32>(FoundReplay->StreamInfo.L ...
FInstancedStruct member uproperties are not cached when "Generate Optimized Blueprint Component Data" is enabled
UE - Framework - Blueprint - Nov 18, 2025A licensee has encountered an issue where their FInstancedStruct isn't being gathered into CachedPropertyData when "Generate Optimized Blueprint Component Data" is enabled. The changes in [Link Remo ...
Instanced Actors: Moving element in editor is not undoable
UE - Engine Scaling - Mass - May 30, 2026Context Instanced Actors can be moved by unchecking Lock Instance Locations on an IAM, and double-clicking into the actor → comp → instance to select an instance. Problem Moving an IA via the giz ...
VT Material Instance Crash - "ProducerDesc.BlockHeightInTiles << MipBias == BlockHeightInTiles"
UE - Graphics Features - Oct 4, 2021Assertion failed: ProducerDesc.BlockHeightInTiles << MipBias == BlockHeightInTiles [Link Removed] [Line: 229] ...
Editor will crash when Blueprint Details Panel is dragged across the Event Graph
Tools - May 6, 2015When dragging the Details Panel in a Blueprint across the event graph the editor will crash. [Link Removed] ...
Crash when creating new projects or converting copies of old ones in Japanese
UE - Editor - UI Systems - Slate - Dec 4, 2014There's a crash in FCharacterList::GetKerning() when using the editor in Japanese that is apparently fixed in one of these three changelists: CL# 2370014, 2370050, and 2370040 But they were not ...
Blueprint 'Select' node: nodes connect to all input pins are evaluated while only one input is needed
UE - Gameplay - Blueprint - Aug 15, 2015Originally marked Won't Fix in 2017. Issue reopened on May 1, 2024. All inputs of a Select blueprint node are evaluated, even though in the end only one value is selected. This is wasteful work. ...
tvOS becomes non responsive after killing a launched on app from Mac
UE - Platform - Mobile - Sep 28, 2016tvOS locks up with the following message being repeated in the device log:Sep 28 10:27:50 Apple-TV-Joey UE4Game[610] <Notice>: [2016.09.28-14.27.50:752][188]LogHttp:Display: Sleeping 0.5s to wait fo ...
Controller::GetPawn() returns NULL in 4.9
UE - Gameplay - Sep 3, 2015Making a call to GetPawn in an AIController class will return NULL which will crash when that return value is used. This is a regression as the call is made successfully in 4.8.3. Working CL: Work ...