Not sure what is causing them, the other side of mesh is flat so it shouldnt pick other side of baking box for it for front. Maps are baked all in tga non compressed. I get artifacts on AO map aswell, however they look different there.
Tga does not support 16 bit. Save as Tif or something, convert to 8-bit then save as tga. Or you could keep 16 bit and save as png. Though I do not know how efficient that is.
Ok so now the problem with previous artifacts is stored…however now i get new type of artifacts. I did some google search and found that many have those if using 16bit-8bit conversion method. Is there way to get rid of those, or more importantly what is causing them? http://prntscr.com/8dly8x
that’s what dithering artifacts look like(in your last picture). Simple solution is to save your normal as 16 TIFF from xNormal and bring into Photoshop, save it as 16-bit PNG(no compression) which UE4 can read just fine. No more dithering and more precision. I use 16 bit PNG all the time for normal maps. Though the dithering won’t be visible once you apply a Albedo texture.