Auto Exposure in Static Mesh Editor whites out the viewport when Vert Colors is enabled

In the Static Mesh Editor, Enabling Vert Colors causes high exposure in the viewport.

Workaround
Disable Auto Exposure in the Project Settings > Rendering > Default Settings

This is a Regression as it does not happen in 4.15.2

1. Open any project
2. Place a sphere in the level
3. Right click the sphere in the viewport
4. Select Edit Sphere
5. Enable Vert Colors in the Tool bar of the Static Mesh Editor
6. Zoom out

Results: The viewport becomes white with over exposure

Expected Results: There is no over exposure, lighting remains consistent