My Beveled Cube creates wrong normal maps - the marked area should be a continuous gradient, but it's multiple gradients in the wrong direction.

Hey kkyl3r , could you share what the high poly object looks like as well? I can't find the problem in the screenshot above. 

Thanks for the extra details, that is interesting indeed. Are you mirroring UV's at all? Something like that might happen if two islands are overlapping but one needs to be flipped vertically. 

Hmm, if that's not it, I don't know what the answer would be. If you want you can upload the file to: http://pasteall.org/blend/ and I can take a look at it later on in the week.