“ECONNRESET” means the other side of the TCP conversation abruptly closed its end of the connection. This is most probably due to one or more application protocol errors. You could look at the API server logs to see if it complains about something.
I had a similar problem where apps started erroring out after an upgrade of Node. I believe this can be traced back to Node release v0.9.10 this item:
net: don’t suppress ECONNRESET (Ben Noordhuis)
Previous versions wouldn’t error out on interruptions from the client. A break in the connection from the client throws the error ECONNRESET in Node. I believe this is intended functionality for Node, so the fix (at least for me) was to handle the error, which I believe you did in unCaught exceptions. Although I handle it in the net.socket handler.