Unable to add pro-builder game objects in prefab editor

Steps to repro:
1. Open attached or create a new project
2. Window > package manager > install pro builder
3. Drag any game object to project window to create its prefab
4. Open prefab editor
5. Right-click > 3D object > Pro builder cube

Actual result:
1. Pro builder game object is visible in the scene view, however, game object is not created in the hierarchy
2. Close prefab editor and return to the scene view > Pro builder game object is not visible
3. Open prefab editor again > the game object is missing from here as well even though it was showing earlier

Expected Result:
1. The user should be able to add/edit pro builder game objects in prefab editor

Note:
1. Alternatively, if the game object is generated from pro builder toolbar it's not visible in prefab editor but it's being generated in the scene
2. If a prefab for pro builder game object is created it can be opened and edited in prefab editor

Environment:
Windows and Mac

Occurring with:
2019.1.0a6, 2018.3.0b7, 2018.3.0a6

Probuilder package version: 3.0.9