In the editor, Directionality scene visualization mode is not displaying the expected result.

Reproduction steps:
1) Download the project or create a new scene with an game object.
2) Build the lighting, ensure General GI is set to Directional
3) Change the scene visualization mode from Shaded to Directionality
4) Observe the bug

Notes:
- Reproducible in 5.6.0a6 (af2099d5a7ac) and 5.6.0b2 (5d236ef0678a)
- Works as expected in 5.4.2f2, 5.5.0f3, 5.6.0a5
- GIF attached below shows the expected and current results