alpine ivaw205, 872a nav issues

I recently installed an alpine ivaw205 in dash, with the nve-872a nav, we also installed a kce-300bt bluetooth, with the 422i i pod cable. All of this was installed in a 2007 porsche cayenne. the problem i am having is this.           -when the ipod is playing as a source, and you enter a destination in the nav, if the route is cancelled the ipod freezes. and the only way to get the ipod to play again is to switch sources. (i.e.switch to radio then back to ipod.) i have already switched the head unit, bluetooth , and nav unit. and still the same result. does anyone have ideas as to what the issue could be.