Mi3 notification sound

[danger]

Hi everyone,
I've a little problem with notification, when my phone is plugged with audio jack ...
I've set sound off, just vibration is active, and phone vibrate when get some notification

If i plug it with a jack, the phone sounds to notify something (sms, w app...), even if is in silence mode!

Example
I listen music with my mi3 plugged with an audio jack. Someone writes me in w app, music stop for a while, i get a notification sound, then music restart
(as i said it happens only when phone is plugged)..

This is a bit annoyng, i dont want any sound or alert (except vibration)... Any idea?

Thanks