Level will crash if Landscape material layer can't find LayerInfo file.

Artist had problem open his level after LayerInfo file was deleted

Create landscape actor
Create landscape material (Mat1) with Layer1 and Layer2
Assign material to landscape and create 2 LayerInfo files, paint on landscape
Save as Level1
Duplicate landscape material (Mat2), apply to existing landscape
Save as Level 2
Open Level1
Open Mat1, Delete Layer 2
Delete in asset browser LayerInfo Layer2 file for Layer 2
Save all changes.
Try to open Level2 map.

Here sample from crash log [2016.09.08-18.48.06:318][682]LogLinker:Warning: Can't find file for asset '/Game/EpicInternal/Anton/ArtTests_DesertTheme_sharedassets/OrangeSand_LayerInfo' while loading NULL.
[2016.09.08-18.48.06:319][682]LogLinker:Warning: Can't find file '/Game/EpicInternal/Anton/ArtTests_DesertTheme_sharedassets/OrangeSand_LayerInfo'

As soon I create new LayerInfo file with same name ( Material layer can have any name) I was able to open level