Weird oddities with Windows Phone volume controls

Got a Lumia 1020 a week ago and immediately noticed this

  1. When the phone is on silent, IM+ continued to sound off with any incoming message. This was only when I was in the app, but still extremely weird how if the phone is on 'vibrate only', the app was still able to send audio notifications. I had to manually set the volume to 0 in order for it to stop. How the heck is this possible?
  2. When using headphones, the notification tones still come out from the phone speaker. This is just plain awkward because if I'm listening to music, I don't even hear the notification because it never came through the headphones. Why is that?