Editor crashes when adding weighted layer info!

When ever i try to create layer info in Landscape->PaintLayers mode the editor crashes and give the following report.

Assertion failed: bIsStatic ^ bIsDynamic ^ bIsVolatile [File:/Users/build/Build/++UE4/Sync/Engine/Source/Runtime/Apple/MetalRHI/Private/MetalVertexBuffer.cpp] [Line: 141]