Instance Static Mesh instance doubles when upgrading from 4.18 to 4.19 or higher

Instance Static Mesh instance doubles when upgrading from 4.18 to 4.19 or higher.
According to Licensee, manual check is difficult.

1. Open attached project. This project is 4.18.
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2. Confirm the Instance Static Mesh component of NewBlueprint being spawned at the level.
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3. Close Project. Open that project with 4.19.
4. Instance Static Mesh component instances doubles.
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