Cannot get purge interval for network alias with a dash

In my docker compose (cut down version below), i define the couchbase server with a network alias that has a dash in it and this seems to be getting split by sync gateway and not able to parse the network alias

couchbase-server:
    image: couchbase/server:6.0.4
  sync-gateway:
    image: couchbase/sync-gateway:2.1.3-community
Unable to retrieve server's metadata 
purge interval - will use default value. Get couchbase://couchbase-server//settings/autoCompaction: unsupported protocol scheme "couchbase" -- db.NewDatabaseContext() at database.go:374