1. Open user's attached project "Woodcutting_Axe.zip"
2. Download and import user's attached package: "uploadtool_Woodcutting_Axe.unitypackage"
3. Try to drag imported prefab "axe" into the scene
-- Observe the error "Unable to instantiate prefab. Prefab may be broken"

Expected result: Unity inserts imported prefab in the Scene
Actual result: Prefab gets corrupted during the import and therefore cannot be inserted in the Scene

Reproducible with: 2017.1.5f1, 2017.2.3p3, 2017.4.9f1, 2018.1.9f1, 2018.2.3f1, 2018.3.0a8

Note: This issue is also addressed in the thread. The link is in the edit field down below