p.s. I wasn't sure what to search for this, sorry if its a repeat
Make sure that your Ipod has the latest version of both Itunes and your Ipod's internal software.
When you sync your ipod to Itunes it brings up the screen that shows a picture of your ipod and shows the "memory bar" on the bottom, in the middle of the screen there are two options.
One of them is to UPDATE your ipod, if you have not already done so, this could be causing it.
It says my iPod software is up to date.