PO is going in deleted status though i hit on SAVE

Hi Experts,

I would like to know the issue which we are facing is standard behavior or bug..

Issue:

PO has been created with 2 line items and the same has been replicated to ECC. Now i had opened the PO and deleted both the line items then kept it on saved without clicking order. Automatically PO has got deleted in SRM and the Header status has been changed to DELETED.

Screen shot of BBP_PD:

If its a bug, what could be the issue and how we can fix it.. Is there any note available.. Waiting for your valuable inputs.

Regards

Siva