Every Android that I've seen (incl. Nexus 4) tend to stop playing, if you remove a physical cable. Not nice. Especially if your headset is old and sometimes looses connection for a millisecond or two...
But much much worse, is when the Bluetooth is disconnected/connected. The thing stops playing. And upon connecting resets position to the start! And starts playing! So if you are listening to a 70 minutes chapter of an audiobook, suddenly you have to search for a precise minute in the chapter. A bit frustrating. And even dangerous, as you might have been driving a car at the time.
... sometimes makes me wonder just how many car crashes could have been prevented by a slightly better designed interface of Google Music ...
Audible app never looses position. But I do sometimes play MP3s... Is there Google audiobook player?