Unable to switch the material from Asset selector window when reassigning any material to the sprite

Steps to Reproduce:

1. Create a new project
2. Drag and drop the Bomb sprite into the Scene
3. Click on BombSprite > Inspector > Material > Material selector
4. Select Mask material and then again select Default Material

Expected Result: Material changes

Actual Result: Material has not changed

Working Fine on: 2019.3.0a11, 2019.2.1f1, 2019.1.0f2

Reproducible on: 2019.3.0a12

Environment: Mac 10.14 and Windows 10