Hi Sooraj,
There is as such no fixed pegging relation between SO and supplies after ATP check (at least to my knowledge) until unless you are making very specific ATP check by putting storage location and batch. If it's ATP at plant level then it just checks when is demand and when is supply available and confirms the same. Now supply situation could fluctuate which could even impact ATP also.
In your screen shot it's evident that cumulative ATP quantity is negative. Do you see any supplies in MD04 for this product apart from stock?
Apart from this cross check SAP note
547118 - FAQ: Result of ATP calculation
Point number 4 in the above note.
Check note 153355 - No availability owing to negative ATP quantity
to see the possible reason which is happening in your system, &
1837190 - Non-confirmation in sales documents or deliveries because of inconsistency
This situation could be resolved by doing an ATP check. You can do this in V_V2, but first try in simulation mode to get better understanding. Plus you also need to consider priority sequence to do ATP in this transaction.
By any chance are you doing this in background?
I hope you are able to resolve this.
Regards
Rahul