I would be concerned too if one album was not syncing to my iPod. I found a couple of resources that I think might help.
First, if you are trying to drag the album over to your iPod in iTunes (manual syncing), verify that "Manually manage music and videos" is checked:
You can find more information at the full article:
If you are syncing automatically, I recommend trying to resync. You can resync content to the iPod by unchecking "Sync Music" and then clicking "Apply" and then checking "Sync Music" and then clicking "Apply" again:
You can find the syncing steps in the following article:
I also recommend reviewing the following article for additional steps if the album is still not syncing over:
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