Grass shadows in BlueprintOffice are very dark on mobile

Grass shadows are very dark in BlueprintOffice on tvOS.

It looks the same in Mobile Preview in the editor

Assigning as Samples - Content based on the response to https://jira.ol.epicgames.net/browse/UE-30580 which may be related.

Updated Repro

1. Open BlueprintOffice in the editor
2. Change Preview Rendering Level under Settings to iOS Preview
3. Navigate to the grass in the center of the map.

Old Repro

1. Launch BlueprintOffice on tvOS
2. Look at the grass in the center of the map

Result: Grass shadows are very dark