Delete a doc from syn_gateway using curl

I am trying to delete a doc from couchbase sync_gateway using curl requests and getting the following error in logs

CURL request:- curl -X DELETE http://localhost:4984/litehq/9ccd178866b3e987ba7e793e2f989c96?rev=8-3b64a71bc174660eb96d44f2d3267a3a

Error in logs:-

sync_1 | 2017-12-07 07:14:30.109043 I | http: panic serving already contains rev "4-bae125b103fff20e8765fc44c5fd5a29"
sync_1 | goroutine 654 [running]:
sync_1 | net/http.(*conn).serve.func1(0xc8200c88f0, 0x7f0b1ab79bb0, 0xc8264c4638)
sync_1 | /usr/local/go/src/net/http/server.go:1287 +0xb5
sync_1 |, 0xc821266e10, 0x22, 0xc821dd96b4, 0x22, 0x1, 0x0, 0x0, 0x0, 0x0)
sync_1 | /home/couchbase/jenkins/workspace/sgw-unix-build/1.3.1/community/godeps/src/ +0x277