Yep, it seems in RT GPU rendering has V-ray problem with tiling textures. If I scale down some UV texture and put them over another texture, alpha only coverage new texture size and outside the coverage texture is rendered as black or white as I have set in Color Balance - Default Color. I tested several file types, tga, png, psd and problem persist. Only crossed me in my mind, create small hack for this. Create new alpha which coverage place outside scaled down UV texture and combine together with alpha from scaled down texture, but I dont know how.