Ok, problem solved, when I said before that welding didnt solve it that was because I was only attempting to weld geometry around the area of the problem, selected all and welded and it got rid of it. It was one vert causing the problem, instead of accepting it and moving on, I looked for that damn vert and found it on the other side of the model with no connection whatsoever to the affected edges, not even close.. Even when I collapsed it manually it didn't fix it, only using weld fixed it, which makes no sense... it's the same result.
Oh Max, you silly goose.
(But that still doesnt explain why when I detached the affected polygons it didn't help, I guess Max is just weird.)
Well, thanks for the help!
ah sorry, double post