[0.6.0] Error on upstream entities during sync

[miguel-martinez-tfs]

Trying to sync a yaml file with multiple different upstreams (different ids, names and targets) on Deck 0.6.0 throws the following error on verbose:

GET /acls?size=1000 HTTP/1.1
Host: localhost:8001
User-Agent: Go-http-client/1.1
Accept-Encoding: gzip

HTTP/1.1 200 OK
Content-Length: 23
Access-Control-Allow-Origin: *
Connection: keep-alive
Content-Type: application/json; charset=utf-8
Date: Mon, 04 Nov 2019 19:20:04 GMT
Server: kong/0.35-1
X-Kong-Admin-Request-Id: b66HEmYXMu93vKXNQGhuPhZrACVBNMCk

{"next":null,"data":[]}
Error: inserting upstream into state: entity already exists

The error will not occur if only a single upstream is defined on the yaml file. A workaround exists by synching one upstream at a time, but I expect them to be synched all at once.