New Material Thumbnails are appearing distorted

When creating a new material the thumbnail will start out as the default material sphere but then quickly appear distorted, almost like its zoomed in really close. This does not affect already created materials.

Working in 4.12 at CL 2995799

Edit MattK: This could be a rendering issue. If it appears that way please set it back to Needs Triage

1. Open any project in the editor
2. Right click in the Content browser and select New Material
3. Hit Enter to accept the default name

Result: Thumbnail is distorted instead of showing the default sphere