Why Rigidbody2D gameobject automatically translating to Vector2.zero itself

Hi everyone

Mystery bug occurs once a while. I mean my project work perfectly as i need at most of times.

In my scenario, Series of rigidbody2d ball is shooted by using Ball_Rigidbody2D.AddForce(dir*speed); .

Ball usually hits the wall and bounce little bit, then falls down on floor.

But in rare case when it hits wall it automatically translate to Vector2.zero itself

If i leave it to occur in loop then it will hit very bad Physics2D.Simulate in Profiler. Later lags like hell.

please watch this video to get clear idea on bug:

Im noob but Im aware of few basics physics rules that rigidbody should not be translated via script. If isKinematic is enabled we can translated via script.

I googled a lot to solve this issue, but sadly didn't found any solution. Please help me to fix this bug.

Thank you in advance

 

Ok. Im in Unity 5.1.0f3. Downloading new Unity 5.2. Let me check in it.

Thanks