An actor event in sequencer can't trigger bug?

Hi everyone,
I add four same actors in my scene,

and add this to sequencer, and add event keys

It’s worked!

But the strange thing is, when i restart editor and scene, only first actor ‘LevelArtActorTree’'s event can trigger, other three actor’s(‘LevelArtActorTree2’ ~ ‘LevelArtActorTree4’) event cannot trigger.

And I remove the other three actor’s keys in sequencer and re-add it, it’s worked, all event can tigger. But after restart editor and scene, other three actor’s event can’t trigger again.

Does anyone know what is wrong?
Any help appreciated!