Nether brick along side nether brick stairs,slabs,walls and fences have slightly lighter texture than the cracked and chieseled nether brick. I say the proble is on the normal netherbrick (and slabs, stairs ect) as on the java edition, the texture is dark. Hope that get fixed, cause it ruins some builds' aesthetic. Also, chieseld netherbricks have slitely lighter texture than cracked and they arent directional.