Getting some bizarre artifacting on lightmaps for this static mesh, this is just a lowpoly with flat grey diffuse and a normalmap on it:



I have no idea what is causing this or how to fix it. It isnt happening with other meshes where I used exactly the same process to import and light them. The weirdest thing is when you break the lighting and need to re-bake it ... the weird artifacting is gone and the normalmap starts looking like its actually being rendered.



this is the material


actor properties: