can it be because of changing normalmapping in terrainLighting shader?
For example, i think a blue channel of nomal map should be constant. And red and blue channels of normal maps it should be mixed instead of summing.
I said it here in my last post: http://hub.jmonkeyengine.org/groups/graphics/forum/topic/terrainlighting-frag-ang-lighting-frag-differrent-normalmapping/
Kinda primitve question, but maybee it would work to set default to 0.01 and remove all other workarounds? That wont be much visible, but might be working for nvidia cards, and ati as well. (Or was this already tried?)
ohhh nevermind… just facepalm… yes i checked what i wanted and trully it is normal maps…
so, core devs should fix normalmapping in the terrainLighting shader?
nope, problem in my classes 
i have terrains created from xml files, but it was parsing somehow badly, and dont taked normal maps for textures that it was in xml file.
just a mistake
just a facepalm 