You are my hero! seriously… 
a fast and easy solution, perfect!
thank you sooo much! <3
hmm… that means the material is already instanced?! well, maybe the reason why i cant instance it again
can I get a reference to the terrain material instance in BP somehow? (i could set all my material parameters manually via BP then… this is time consuming and not really flexible but still better than nothing)
the problem is: I already got a complex terrain material and because of the complexity its a lot of work to search & change the parameters (manually by hand inside the material editor)
you mentioned the LOD dithering…
and if i dont use LODs at all? Im generating small maps without LODs… I dont need big maps and LOD support actually…