I heard a rattling noise from my Pocket Reform so I opened it to check.
This little piece of the battery holder had broken off.
It doesn’t seem to have any critical function to me. It it ok to just leave it like that?
I’m glad it was just plastic so no risk of shorting anything 
Yeah, they’re a little brittle. Same happened to me and had the same feeling of relief that it wasn’t a screw or something that potentially might cause a short.
I’m going to guess that’s the same part that’s been rattling in mine since arrival. I should probably open it up finally and rescue it. 
So I had the same thing a long while ago and I have some advice: get it fixed or you’ll end up trying to solder a new thermistor on at some point:
If the battery is not held in place, it can jiggle around and dislodge this component. I was lucky, it’s only torn up some of the ground plane so I can bodge a fix, but otherwise I’d be looking at a whole charger board replacement if it had been the other trace.
This can very much be a ticking timebomb - I’ve actually repaired this once already without having figured out why it happened in the first place. My fix was coated in superglue, and even that didn’t save it.
