Journey to Bluetooth Keyboard interference on iMac

I uploaded the default demo in the IDE:

var on = false;
setInterval(function() {
on = !on;
LED1.write(on);
}, 500);

The ghost keyboard, this time, only used left and right arrows, though last time I remember characters.

This time the ghost only appeared after disconnecting and reconnecting.

It made it impossible to edit the demo to change it.

I will try harder with the ubuntu machine, thanks for the tip.