Audiobooks not fast forwarding.

When I press the center button of my iPod Classic (160 GB) twice to get the fast forward/rewind scroll (diamond icon), no matter how many times I try to fast forward to a later point in the file, the icon always resets to the first few seconds of that file. In other words, I cannot fast-forward when listening to audiobooks. If I attempt to rewind or fast forward after the file has been playing for any period of time, the icon resets to within the first few seconds of the start of the file.

This function works perfectly with audio files and movie files. It only fails to work with books tagged as Audiobooks.

Any ideas? I have done the reset process several times. I hesitate to do a full restore, but that's probably next.

This may be an entirely different issue, but I thought I'd also mention that I use my iPod extensively, due to a daily 45 mile one-way commute, playing through my 2011 VW Jetta audio system through the MDI connector (a digital interface that permits me to control the iPod through the touch-screen on the radio, as well as buttons on the steering wheel). Randomly, while playing audiobooks (haven't noticed with music), the iPod resets to the start of the selected file (in other words, I'm at 7:53 in chapter 7 of some book, and it suddenly resets to 0:00 in chapter 7--I do hear a brief bit of audio distortion just as it happens). With my iPod in its current state, this means that I can't fast-forward back to the point where the iPod reset to zero!

My iPod has the same fast-forward problem when using the VW MDI controls to move to a different point in the file--exactly the same as trying to move forward with the click wheel.

I wonder if these two anomalies are related, and is it possible the VW MDI (digital audio interface) somehow corrupted the iPod's operating system?

Thanks for any sage advice!