Assigned sprites are missing from the scene when a package is imported in the latest version of Unity

Steps to Repro:

1. Open a new project
2. Import attached package
3. Open AreaEffector scene

OR

1. Open a new Project in 2018.1.0f1
2. Import any sprite and make few instances
3. Changed the sprites to different compressions
4. Drag all in the scene.
5. Quit Unity Editor
6. Open the same project in 2019.1.0a11

Actual Result: Sprite is missing in sprite renderer from Background, Bottom, Left etc game objects

Expected Result: Package imports successfully or project opens without missing sprites

Reproducible in:
Version 2019.1.0a12 (5aef5b61e109)Tue, 04 Dec 2018 13:51:42 GMTBranch: trunk,
2019.1.0a11, 2019.1.0a10, 2019.1.0a9

Working Fine:
2019.1.0a8, 2019.1.0a1, 2018.3.0f1, 2018.2.0f2

Environment:
Windows 10 and Mac 10.13

Note: For reference, use attached project