Hi Vineeth,
Your scenaio is bit different compared to SAP Notes you have provided.
If you check the notes, it was clearly mentioned "already created notification is assigned in the object list", but in your case, you are trying to create a work order and notification in back ground.
When i was testing your case, i found after trying to save the work order without having header short text entered and adding the header short text, it was not copied to the Operation automatically, eventually it didn't copy to the notification.
On checking the SAP notes, found other notes, but not sure how much it is relevant to your case.
1721128 - IW31: Header short text is not updated in first operation
Alternatively.... Solutions provided by Jogeswara for making the order header Text field mandatory will work without any issues.
Regards
Terence