Beep setting appears to crash watch

Playing with the 'beep setting to see if it will make noises - but I'm encountering this behaviour:

1. Start with a rebooted watch
   
2. Go into settings Select 'beep' (the initial value shows' undefined')
   
3. change the value to 'On'
   
4. Use the IDE left hand side to try to make it beep - it doesn't.
   
5. Go back to settings and change the value back to 'undefined' (simply to leave it as it was)
   
6. Touch on the left side to move away from the 'beep' menu item. The watch doesn't respond to the touch, and it takes a reboot to get it working again.
   
   

In the IDE the following appears:

Uncaught SyntaxError: Unexpected end of Input
 at line 1 col 1
^
in function "format" called from line 3 col 68
...lue,b.format&&(k=b.format(k)),k=t.translate(""+k),d.selectEd...
                              ^
in function "draw" called from line 1 col 236
...b.onchange(b.value);d.draw()}
                              ^
in function "select" called from line 1 col 22
b?d.move(b):d.select()
                     ^
in function "cb" called from line 1 col 8
b();cb();
       ^
in function called from system
 at line 1 col 1

Obvious remedy to avoid this, don't try to set 'beep to 'undefined'! But it looks like a bug.

And should it actually be able to make a beep of sorts? The docs (which probably refer to bangle 1) say that you can set 'beep' to vibrate and it will simulate a beep using the vibration motor, but there's no such setting available on the Bangle 2.