Steps to reproduce:
1. Create a new project with the HDRP package
2. Import the provided custom package "DecalTestAssets.unitypackage"
3. Open "BugReportDecal" Scene inside the "_BugReportDecal" folder
4. Select and drop the "DecalBurn" Prefab anywhere in the Scene view

Expected results: a decal duplicate does not appear at a random location on a GameObject
Actual results: a decal duplicate appears at a random location on a GameObject

Reproducible with: HDRP 7.1.5 (2019.3.0b4, 2019.3.0f3, 2020.1.0a16)
Not reproducible with: HDRP 4.1.0 (2018.4.14f1), HDRP 6.9.2 (2019.2.16f1), HDRP 7.0.1 (2019.3.0b3)
Could not test with 2017.4.35f1 due to HDRP not existing

Note:
-Instantiating new "DecalBurn" Prefabs generate another ghost decal at the same position as the previous ones.
-Discarding changes in the scene doesn't get rid of this ghost decal. Restarting Unity gets rid of it.