brake line leak

[ex-x-fire]

I had a line rust out and it started leaking on our 09 hatch, the line is mostly coated except the last bit where the tube nut is. Why did they do that? I'm pretty sure I put a little grease on that section a year or two ago, I guess I was too late. This picture is similar to what Toyota does, not coating all the way. I fixed it up with a 4' section and cut off the coating to flare the lines up at a union.