Particle record feature in the matinee seems not properly working in the Editor.
When trying to play in the matinee with recorded keys, the Engine will crash with Access violation - code c0000005.
This issue is still reproduced when switching all the modules into Seed module which are enabled to in the Cascade.
1) Create a particle system.
2) Open the particle system. Save.
3) Put particle on the level.
4) Create an matinee actor(legacy)
5) Add a particle group after selecting the particle emitter.
6) Create a new particle record track.
7) Press Add key button to add a new key at time 0
8) Right click in the particle record track
9) Select start recording particles.
10) Press play button in the matinee
11) Right click in the particle record track when timeline reached at the end.
12) Select stop recording particles.
13) Go to timeline 0 in the matinee
14) Press play in the matinee
expected: recorded particle is replayed
result: engine crash.
Access violation - code c0000005 (first/second chance not available) UE4Editor_Engine!FDynamicSpriteEmitterData::CreateVertexFactory() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\particles\particlesystemrender.cpp:1011] UE4Editor_Engine!FParticleSystemSceneProxy::AddEmitterVertexFactory() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\public\particlehelper.h:2596] UE4Editor_Engine!FParticleSystemSceneProxy::UpdateVertexFactories() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\public\particlehelper.h:2609] UE4Editor_Engine!FParticleSystemSceneProxy::UpdateData_RenderThread() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\particles\particlesystemrender.cpp:7008] UE4Editor_Engine!`FParticleSystemSceneProxy::UpdateData'::`2'::EURCMacro_ParticleUpdateDataCommand::DoTask() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\particles\particlesystemrender.cpp:6979] UE4Editor_Engine!TGraphTask<`FParticleSystemSceneProxy::UpdateData'::`2'::EURCMacro_ParticleUpdateDataCommand>::ExecuteTask() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:784] UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:651] UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:560] UE4Editor_RenderCore!RenderingThreadMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\rendercore\private\renderingthread.cpp:327] UE4Editor_RenderCore!FRenderingThread::Run() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\rendercore\private\renderingthread.cpp:461] UE4Editor_Core!FRunnableThreadWin::Run() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:76]
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-51456 in the post.