"Sprite Mode" is not auto-populated when switching Texture Type to "Sprite (2D and UI)"

1. Create a new project in 3D mode
2. Right-click import a texture/sprite
3. Click on the imported texture/sprite
4. In Inspector, change Texture Type from "Default" to "Sprite (2D and UI)"

Observed result: The "Sprite Mode" dropdown selector is blank.
Expected result: The "Sprite Mode"dropdown selector auto-selects "Single" as the default.

Occurring on: 5.5.2p1, 5.5.2p2, 5.6.0f1, 2017.1.0a2 onwards
Not occurring: 2017.1.0a1, 5.5.2f1 and older