iTunes not moving new music to iPod since upgrade to 12.1.2.27

iPod classic, no problems synching music UNTIL I upgraded to 12.1.2.27. Now new music,visible in iTunes, will not synch. What's especially weird is that I SAW iTunes display that it was synching the music via the bar on top - but nothing since the upgrade has actually been moved to my iPod, as far as I can tell.

The albums are checked in iTunes, not unchecked.

No songs from the albums are on the Songs list. The albums are not in the Compilation list. They're just not there.

What do I do?