The only thing I ever get is the ping to say its opening or closing, along with the dash indication.
Never noticed the music cutting out although think its like the NAV commands and it should then mute it momentarily.
As with Tree, we have had constant rain these last couple of days so next opportunity will give it a go.
yes, it does do it just when the top is almost closed or just opening. I don't get a ping or any visual indication that the movement is finished. The only way I know is by looking at the latches at the top of the windshield.
My Miata NC equipped with a Bose sound system did this too. Mazda explained that it was the Bose switching from a top down or top up configuration. I have never seen this mentioned in the GTK but it may very well be a Bose feature for convertible cars.