We are able to create a deal successfully using the REST API. According to our logic, if a deal doesn't exist we use the create deal API to create a new one. Else update the deal if it is already present. We use a specific id as a property that will always have a unique value which is used to search for a deal.

The problem is that after creating a new deal say D1, it creates a new deal D2 if we try to update D1. This happens only for the first updation try. After that we are able to update D1 successfully.