Parent actor missing in subscene after reopening

Attaching a particle to the bone of the actor spawning with the parent's sequence, once closed it will be missing.

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Content/Sequencer/CutMaster
Content/Sequencer/SubScene_effects

1. Master sequencer add subscene track.
2. Master sequencer add spawnable skeletal mesh.
3. subscene track set to sub sequence.
4. Sub sequencer add particle.
5. Particle in sub sequencer attach to bone from spawnable skeletal mesh at parent.
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6. Save and reopen it will be missing.
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