Is it maybe because you changed the number of vertices while editing it? That's happened to me many, many times, so maybe it happened to you, too.
Maybe try right-clicking on both of them and going to Properties to check the number of vertices could show you what the problem is?
Was this directed at me?
If so I don't think this is the cause. Even if I don't edit anything it still doesn't work.
I am indeed using Vish's method. And about your problem, could you clarify a bit more or add pictures? I'm sure I could help you as I've had a similar problem, but it was when I still used the patching method.....
I have the same problem as you. Although that method is easier I don't believe there is a fix for this. I explained the situation to both MarioKart and Vish but neither of them had a solution.
But I am probably and hopefully wrong. I have not tried patching afterward mainly because I want to be able to use the no patch method without it screwing up, but I haven't found a way around it.
For now I'm just using MarioKarts method. (But as I've explained in my last post, I'm having trouble with that as well)