Problem with Face Edges selection

Hello,

I am trying to select the edges of the face of a solid for a Section Inertia Analysis. However, the selection does something strange at a very small part of the selection. Given that little something, it is not possible to get the solid analysis and instead it gives me a hollow analysis. Here are some screenshots of the problem.

Is there a way to prevent NX from doing this? I am using NX 11

I appreciate your help.

Jorge