If you want to run two nodes in dev mode on the same computer, you'll need two special CLI options to make it work.
This is because each process that you use to run an app requires two ports. If each instance of the app is running on the same two ports, then they will fail to communicate with one another. There is a port for the web server, and there is a port for the DHT process that gossips with other nodes. We need to adjust both ports.
hcdev --agentID=anystring --DHTport=6284 web 4142