Seek forward or back using a USB flash-drive, and it would either take a while to decide to do it, or it would forward/rewind inside the song, instead of actually seeking to the next or previous song.
Just started happening one day, after the MFT display didn't light up right away after starting. It took an extra 10-15 seconds that day, and then the seek button acted up.
So, took out the "Delayed Reboot" flash drive, stuck it in, waited it to "install app", shutdown the engine, opened the door so the radio went off, started it back up, and it went through the reboot cycle.
No more wonky seek button. Whew!
The delayed reboot zip file is available on the web, I'm not sure how legal it is to redistribute otherwise I would.