Boxcast Hit things, but return invalid normal.

I'm using boxcast hit, and sometime this happen to me, any ideas ? (as image),



right now I'm trying to avoid this issue by check if the value IsNaN, for everytime Boxcast said it hit something.
but I can't 100% reproduce this, it append random on same code.

 

turn out the reason was the box size.
I try to detect the surface collision by using

Code (CSharp):

1. new Vector3(float.Epsilon, 10f, float.Epsilon);

this issue will appear if using float.Epsilon in the size reference,
it's able to reproduce by specific coordinates & distance.

Note : not all of them, but some of them, however when you located it can always reproduce in same position.
In my case I use Gizmos draw to debug.

I guess the glitch happen during the normal vector calculation :

was the input "float.Epsilon" being divide by something and round down become zero.
and that being used as divisor.​

so the solution for me was simply change Epsilon to "0.0001f".... a small enough number for my calculation.