Help with normals for landscape

I am very new to Unreal and am having issues setting up my first landscape. I have tried googling this issue extensively and not found anything that relates - I apologise if this is something simple which has already been covered hundreds of times!

I can apply most textures to my landscape material (baseColour, roughness etc) and verify that they appear as expected in the viewport, but as soon as I add the normal map everything is covered in deep shadows and large chequered squares - much bigger than the individual texture tiles. If I leave the camera stationary the light slowly gets brighter over time, until I change anything or move the camera - then it instantly goes dark and slowly gets brighter again…

I have tried rebuilding the lighting, and switching DXT5 normals on and off in the project settings and nothing is making a difference.

I’m sure the fix won’t be too complicated, but I’m going a bit mad trying to work it out on my own!


First off, the way the light is slowly changing like that is auto expsoure, it can be turned off in the project settings.

On the main issue, I’m not entirely sure, but I don’t think landscape are great at working with a default material, it probably needs to specifically be a layered landscape material.

Doesn’t have to be elaberate, it can have just one layer, no problem, but it needs to be make for landscape: