When you take the inner 'puck' out from the watch casing, it should be pretty easy to pull the brown GPS antenna away and see if the little connector is actually pushed in to the PCB. I guess it's possible it just isn't connected.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
That's a good point. If you're willing to look inside it'd be great if you could follow this video: https://www.espruino.com/Bangle.js+Disassembly
When you take the inner 'puck' out from the watch casing, it should be pretty easy to pull the brown GPS antenna away and see if the little connector is actually pushed in to the PCB. I guess it's possible it just isn't connected.