Keep crashing after building light

the game run fine, but once i build the light and click play, it’s keep crashing, and corrupting the map. And now i can’t open it anymore (i did a backup before so it’s fine)

that the log

!Id:8959d25192df750b6ecac41297dbb210

Unknown exception - code 00000001 (first/second chance not available)

Assertion failed: TheModel->Nodes.IsValidIndex( NodeIdx ) [File: D :\BuildFarm\buildmachine_++depot+UE4-Releases+4.4\Engine\Source\Runtime\Engine\Private\ModelRender.cpp] [Line: 99]
Invalid Node Index, Idx:2086, Num:207

KERNELBASE + 37901 bytes
UE4Editor_Core + 3095292 bytes
UE4Editor_Core + 1661738 bytes
UE4Editor_Core + 1541824 bytes
UE4Editor_Engine + 5124051 bytes
UE4Editor_Engine + 5314098 bytes
UE4Editor_CoreUObject + 899050 bytes
UE4Editor_Engine + 14259471 bytes
UE4Editor_CoreUObject + 899050 bytes
UE4Editor_CoreUObject + 1329894 bytes
UE4Editor_CoreUObject + 1400728 bytes
UE4Editor_UnrealEd + 2593508 bytes
UE4Editor_UnrealEd + 2540781 bytes
UE4Editor_UnrealEd + 2466449 bytes
UE4Editor_UnrealEd + 5632240 bytes
UE4Editor_UnrealEd + 2959412 bytes
UE4Editor_UnrealEd + 2962229 bytes
UE4Editor_LevelEditor + 1020586 bytes
UE4Editor_Slate + 545350 bytes
UE4Editor_Slate + 1883687 bytes
UE4Editor_Slate + 1920472 bytes
UE4Editor_Slate + 1690972 bytes
UE4Editor_Slate + 2512538 bytes
UE4Editor_Slate + 2748777 bytes
UE4Editor_Slate + 794079 bytes
UE4Editor_Slate + 727433 bytes
UE4Editor_Core + 2503893 bytes
UE4Editor_Core + 2422897 bytes
UE4Editor_Core + 2508318 bytes
UE4Editor_Core + 2410210 bytes
user32 + 105425 bytes
user32 + 104666 bytes
UE4Editor_Core + 2509510 bytes
UE4Editor!FEngineLoop::Tick() + 2877 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.4\engine\source\runtime\launch\private\launchengineloop.cpp:2080]
UE4Editor!GuardedMain() + 476 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.4\engine\source\runtime\launch\private\launch.cpp:133]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.4\engine\source\runtime\launch\private\windows\launchwindows.cpp:125]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.4\engine\source\runtime\launch\private\windows\launchwindows.cpp:201]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

Reason why ?

Hi Ga.rheault,

Please post this to the answerhub at http://answers.unrealengine.com so we can better assist you. Thank you.

Just did, thanks