Under section 10 Hindu marriage act similar to divorce

Respected lawyers My sister is about to get remarried she filed a petition and got a decree of divorce u/s 10 in additional principal judge family court Gurgaon when we shared the document with her would be husband they said that this is not decree of divorce though it is clearly written that the marriage is dissolved by a decree of divorce as per the terms and conditions mentioned in compromise.in case u need the document for verification I can send it in email .please tell me why they are saying this is not decree of divorce