This is a common problem with AVIC Z units. The radio signal on you phone interfered with the satellite receiver. This is a problem that Pioneer needs to address. You will notice that any time you make a call that is not brief your signal will be off for as long as 10 minutes.
eh? That's a new one on me. I've had five people in my car all taking on their phones and never had a gps tracking problem. Moreover, my cell phone has a GPS receiver in it and I've never had a problem tracking.
The issue here is caused by either the user pushing the "end call" button in the upper right portion of the screen or the user selecting "end call" on the available steering wheel remote. The later option is essentially a remote call for the end button on the screen. The "End Call" button in the screen is a float button that is interpreting its selection twice: once to end the call and a second time as selecting the area directly under it as a location on the map thus causing in the scroll function to initiate.