Resolution:
This is not a BW specific issue or a defect of BW. This is a browser specific problem. The browser itself sends the request to the HTTP receiver twice, and as the HTTP receiver intended to serve the incoming request, it spawns twice, but you have hit the URL once from the browser. So you can think that it is a BW related issue or it is a BW defect that will execute the request twice. You can verify this scenario by capturing the incoming request from the browser to the HTTP Receiver. For this purpose you can use a third party tool such as tcptrace or tcpstream. Capture the incoming request from the browser. Then you will be able to see that your browser sends the same request twice. As a result, the BW HTTP receiver creates two jobs. You can try with different browsers to overcome this issue with Chrome, IE, Opera or Mozilla.

BW Processes with a HTTP receiver starter executes twice.