Hopefully it’s very rare that you encounter a difference between local runs and those on morph.io. As @otherchirps says over on the other topic it looks like you hit quite the corner case!
Hmm, that definitely shouldn’t happen. Connection reset by peer may have been a temporary problem, could you try again?
Another random possibility is that the latest version of Ruby I’ve used it on is 2.2.0. Surely that can’t be the problem but could you also try running it on 2.2.0?