Bangle.js 2 not vibrating on message

Just to make sure, There's the setting under Settings->Apps->Messages->Vibrate where there are a plethora of vibration options to choose from. But you've probably been there already.

You can try Settings->Utils->Rewrite Settings and see if that helps.

There's also Settings->Alerts->Quiet mode, could you have turned that on? (I don't know exactly how it functions)

As some kind of last resort (well there are even 'laster' resorts) you could try Settings->Utils->Reset Settings. Or reinstall the Messages app.

How it works for me:

1. I send a debug message from Gadgetbridge ('Unknown' type).
   
2. The messages app loads on the watch and displays the message and the watch vibrates. (If I'm on the clock, otherwise I only get the notification icon and vibration)