Description

The crash only occurs when enabling the channels of lights that are part of the "BP_SphereLight" or "SM_CubeLight". Enabling the channels of a single "PointLight" or "SpotLight" doesn't crash the editor. Regression is marked as "No" as the issue occurs in Release 5.7.2, using Binary (Launcher) //UE5/Main - CL 49658320.

Steps to Reproduce
  1. Open the \Sandbox\VirtualProduction\QAVirtualProduction\QAVirtualProduction.uproject
  2. Open the "L_LightMixer" level
  3. Open the "Light Mixer" panel under Window > Light Mixer
  4. Select any light under the "BP_SphereLight" or "SM_CubeLight" actors (e.g. "SpotLight" or "PointLight")
  5. Click any of the "Lighting Channels", either "Channel 1" or " Channel 2"

Actual Outcome: The editor crashes to Assertion Failed after enabling a light's "Lighting Channels" from the "Light Mixer" panel

Expected Outcome: The "Lighting Channels" are enabled without crashing the editor

Callstack

Assertion failed: IsValid() [[Link Removed]|File:C:\P4_FNMain\Engine\Source\Runtime\Core\Public\Templates\SharedPointer.h]] [Line: 1119] UnrealEditor_Core!FDebugCheckVerifyFailedImpl2() [C:\P4_FNMain\Engine\Source\Runtime\Core\Private\Misc\AssertionMacros.cpp:786] UnrealEditor_DetailCustomizations!FLightingChannelsCustomizationOnButtonCheckedStateChanged() [C:\P4_FNMain\Engine\Source\Editor\DetailCustomizations\Private\LightingChannelsCustomization.cpp:145] UnrealEditor_DetailCustomizations!TBaseSPMethodDelegateInstance<1,FLightingChannelsCustomization const ,1,void _cdecl(enum ECheckBoxState),FDefaultDelegateUserPolicy,unsigned int>ExecuteIfSafe() [C:\P4_FNMain\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:284] UnrealEditor_Slate!TDelegate<void __cdecl(enum ECheckBoxState),FDefaultDelegateUserPolicy>ExecuteIfBound() [C:\P4_FNMain\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:644] UnrealEditor_Slate!SCheckBoxToggleCheckedState() [C:\P4_FNMain\Engine\Source\Runtime\Slate\Private\Widgets\Input\SCheckBox.cpp:397] UnrealEditor_Slate!SCheckBoxOnMouseButtonUp() [C:\P4_FNMain\Engine\Source\Runtime\Slate\Private\Widgets\Input\SCheckBox.cpp:262] UnrealEditor_Slate!FEventRouterRoute<FReply,FEventRouterFToLeafmostPolicy,FPointerEvent,{{FSlateApplication::RoutePointerUpEvent'::}}8'<lambda_2> >() [C:\P4_FNMain\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:466] UnrealEditor_Slate!FSlateApplicationRoutePointerUpEvent() [C:\P4_FNMain\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5502] UnrealEditor_Slate!FSlateApplicationProcessMouseButtonUpEvent() [C:\P4_FNMain\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:6087] UnrealEditor_Slate!FSlateApplicationOnMouseUp() [C:\P4_FNMain\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:6043] UnrealEditor_ApplicationCore!FWindowsApplicationProcessDeferredMessage() [C:\P4_FNMain\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:3530] UnrealEditor_ApplicationCore!FWindowsApplicationDeferMessage() [C:\P4_FNMain\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:4230] UnrealEditor_ApplicationCore!FWindowsApplicationProcessMessage() [C:\P4_FNMain\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2450] UnrealEditor_ApplicationCore!FWindowsApplicationAppWndProc() [C:\P4_FNMain\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2243] user32 user32 UnrealEditor_ApplicationCore!FWindowsPlatformApplicationMiscPumpMessages() [C:\P4_FNMain\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsPlatformApplicationMisc.cpp:234] UnrealEditor!FEngineLoopTick() [C:\P4_FNMain\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5765] UnrealEditor!GuardedMain() [C:\P4_FNMain\Engine\Source\Runtime\Launch\Private\Launch.cpp:190] UnrealEditor!GuardedMainWrapper() [C:\P4_FNMain\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:123] UnrealEditor!LaunchWindowsStartup() [C:\P4_FNMain\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:277] UnrealEditor!WinMain() [C:\P4_FNMain\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:336] UnrealEditor!_scrt_common_main_seh() [D:\a_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288] kernel32 ntdll

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Unresolved
ComponentUE - CAPT - Tools
Affects Versions5.8
Target Fix5.8.5
CreatedFeb 9, 2026
UpdatedSep 21, 2026
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