A320 Captain reports being chimed by the Flight Attendant's at the same time a routing change was being issued by ATC.

Narrative

In cruise ATC told us to overfly DOBNE Intersection. During the call with ATC the Flight Attendant's called with a maintenance writeup that was distracting; especially the overly loud chime that the Airbus has. We were told to overfly DOBNE and given a new arrival into SFO. While I was inputting new route the First Officer noticed the aircraft had started an early turn and we were not overflying DOBNE. The First Officer used heading mode to turn towards the waypoint so that we would overfly it. ATC then called and gave us a heading to overfly the waypoint which we did. A few minutes later ATC said we were now clear of Joshua Airspace and we were cleared direct. I believe we did fly over the waypoint with the First Officers intervention. The Airbus does have a tendency to cut corners over waypoints. In retrospect; I should have just used the overfly button at DOBNE to avoid any confusion. It would have been helpful if ATC would have told us of Joshua's Airspace and the need for an overfly rather than the usual route the FMGC would follow.