Landscape - Material - LayerBlend issues

I’m new with UE, found some nice tutorials on createing material for landscapes using Layer Blend and Layer Info to paint textures I wanted. Two problems I am facing:

  1. it is constantly compling Shaders. I’ve read somewhere to prepaint terrain with each layer, so I did that. Didn’t help. Still, after doing so, I’ll paint whole terrain with ‘Mud’ and then I move to grass layer. The moment I start drawing, terrain goes grey and shaders are being compiled. Once they are compiled, I can paint that layer, but the moment I move to another one, eg sand, terrain goes gray compiles. If afterwards I move back to grass, same thing happen. Although, sometimes it actually starts painting, but only for a few strokes, and then starts rebuilding shaders.

  2. sometimes, once it finishes rebuilding shaders, some of the terrain chunks (squares) stay grey and no mather what I do, I can’t paint on it. Nothing happens. Texture doesn’t show up, shaders are not recompiled, nothing. If another part of landscape forces shader compilation, the brokne chunks stay broken.

I’ve tried it in three different projects, every time same result.