node not printing full object
At first I thought this was an interesting problem, but then I realized it makes no sense. I tried doing various similar things in a js file and nodeing it but I can't replicate what you encountered.
Either the log message doesn't come from the console.log, or that this problem can't be replicated after restarting the server (something went wrong in V8 for a moment?).
Have you tried changing the log arugment to something like prun_item.components[0].quantity?
Or perhaps your original code is a lot more complex than this and modifying the object returned from _.find does not modify the object that you console.log, which is the only logical explanation for this.