Reproduction steps:
1. Open the user's attached project "DragDropBug.zip"
2. In the Project window open Assets/Scenes/BugTest.unity
3. In the Project window go to Assets/Art/Particles, select the "ButterFlies.vfx" asset, drag it into the Scene view and drop it on the Terrain

Expected result: A new GameObject is created in the Hierarchy window when dragging and dropping the asset into the Scene view
Actual result: A new GameObject is directly parented to a GameObject the asset is dragged and dropped on in the Scene view

Reproducible with: 10.0.0-preview.27, 10.1.0 (2020.2.0b8, 2021.1.0a2)
Not reproducible with: 7.3.1, 7.5.1 (2019.4.12f1), 8.2.0, 9.0.0-preview.71 (2020.1.10f1)
Cannot test with: 2018.4.28f1 (errors with the VFX package)

Notes:
- This issue happens not only with the "ButterFlies.vfx" asset but with any VFX asset
- Creating a GameObject like a Cube or a Plane then dragging and dropping the VFX asset on it will create the same issue