The licensee has traced the issue back to a divide by zero in UParticleModuleTypeDataBeam2::Update. If the Target and Source are the same then the beams magnitude will be zero. When there is a Noise module the TravelRatio will be the TrueMagnitude/FullMagnitude, and FullMagnitude will be zero.
I tested replacing float FullMagnitude = BeamData->Direction.Size(); with float FullMagnitude = FMath::Max(BeamData->Direction.Size(), 0.001f); and the crash did not occur (Shelved CL 9001727).
RESULT
The editor will crash.
Assertion failed: CheckVertexCount <= Source.VertexCount [Link Removed] [Line: 4857]
UE4Editor_Core!FWindowsErrorOutputDevice::Serialize() [e:\_release4.23\engine\source\runtime\core\private\windows\windowserroroutputdevice.cpp:79]
UE4Editor_Core!FOutputDevice::LogfImpl() [e:\_release4.23\engine\source\runtime\core\private\misc\outputdevice.cpp:71]
UE4Editor_Core!AssertFailedImplV() [e:\_release4.23\engine\source\runtime\core\private\misc\assertionmacros.cpp:101]
UE4Editor_Core!FDebug::CheckVerifyFailedImpl() [e:\_release4.23\engine\source\runtime\core\private\misc\assertionmacros.cpp:445]
UE4Editor_Engine!FDynamicBeam2EmitterData::FillData_Noise() [e:\_release4.23\engine\source\runtime\engine\private\particles\particlesystemrender.cpp:4857]
UE4Editor_Engine!FDynamicBeam2EmitterData::GetDynamicMeshElementsEmitter() [e:\_release4.23\engine\source\runtime\engine\private\particles\particlesystemrender.cpp:2787]
UE4Editor_Engine!FParticleSystemSceneProxy::GetDynamicMeshElements() [e:\_release4.23\engine\source\runtime\engine\private\particles\particlesystemrender.cpp:7008]
UE4Editor_Renderer!FSceneRenderer::GatherDynamicMeshElements() [e:\_release4.23\engine\source\runtime\renderer\private\scenevisibility.cpp:2807]
UE4Editor_Renderer!FSceneRenderer::ComputeViewVisibility() [e:\_release4.23\engine\source\runtime\renderer\private\scenevisibility.cpp:3869]
UE4Editor_Renderer!FDeferredShadingSceneRenderer::InitViews() [e:\_release4.23\engine\source\runtime\renderer\private\scenevisibility.cpp:4157]
UE4Editor_Renderer!FDeferredShadingSceneRenderer::Render() [e:\_release4.23\engine\source\runtime\renderer\private\deferredshadingrenderer.cpp:934]
UE4Editor_Renderer!RenderViewFamily_RenderThread() [e:\_release4.23\engine\source\runtime\renderer\private\scenerendering.cpp:3242]
UE4Editor_Renderer!TGraphTask<TEnqueueUniqueRenderCommandType<`FRendererModule::BeginRenderingViewFamily'::`27'::FDrawSceneCommandName,<lambda_98974a148448e2faeb6b39d7ee44228d> > >::ExecuteTask() [e:\_release4.23\engine\source\runtime\core\public\async\taskgraphinterfaces.h:847]
UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() [e:\_release4.23\engine\source\runtime\core\private\async\taskgraph.cpp:686]
UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() [e:\_release4.23\engine\source\runtime\core\private\async\taskgraph.cpp:583]
UE4Editor_RenderCore!RenderingThreadMain() [e:\_release4.23\engine\source\runtime\rendercore\private\renderingthread.cpp:340]
UE4Editor_RenderCore!FRenderingThread::Run() [e:\_release4.23\engine\source\runtime\rendercore\private\renderingthread.cpp:471]
UE4Editor_Core!FRunnableThreadWin::Run() [e:_release4.23\engine\source\runtime\core\private\windows\windowsrunnablethread.c
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-80729 in the post.