physics rolling error( included sample and simple demo)

link sampleproject download

link webplayer

Ball, plane A, plane B

plane A and plane B is flat but ball collision

Rolling the ball on the same height two planes ...... when it pass other objects, it comes out to crash though it is flat

Samples will be aware of the shot button pressed Go roll will find that it does OnCollision

Two terrain is flat. But the ball to crash. Is this a problem? The terrain mesh is made of two objects with different color appears on the screen

why do collision? what 's problem?

please help me~