Ah! That explains a lot, Video Podcasts are a mystery on the Classic!
Do you get any messages when you Sync these Podcasts? Some video Podcasts will not play on the iPod Classic and therefore they don't get transferred to the iPod. However, in that situation, I would expect you to see a message telling you something like "Some Podcasts were not transferred to the iPod because they cannot be played on this iPod."
You can't miss the message, so if you don't see it, the Podcasts must be on the iPod somewhere. However, I've noticed that video Podcasts can be almost anywhere on the iPod Classic, not sure why.
For instance, I have video Podcasts from different providers which are all in the iTunes U section in the iTunes library - even though they are not "educational." But, on the iPod, some of them are in the iTunes U section, while others are in the Music section. And guess what? The search facility does not find items in iTunes U! I have inspected the videos in iTunes but I'm unable to see why they should be in different sections of the iPod.
So, first of all, where are these videos in the iTunes library; Podcasts or iTunes U? This may give you a starter about where they are on the iPod and look (obviously) in the iTunes U on the iPod.
If you can't find them in iTunes U, try looking in the Video Playlists. Note, Video Playlists is separate from Playlists, so if necessary, place Video Playlists on your Main Menu. Even then, in the Video Playlists, all is not simple. Also on my Main Menu is Videos/Movies and some of my rogue video Podcasts are in there!
Example:
in the iTunes Library;
- Library/iTunes U/History 106B
- Library/iTunes U/Shulton: Old Spice (adverts)
both in the same section, next to each other.
Start from iPod Classic - Main Menu:
- Videos/Movies/Shulton: Old Spice (- only)
- Videos/Video Playlists/iTunes U/Shulton: Old Spice (- only)
- Video Playlists/iTunes U/Shulton Old Spice (- only)
- Playlists/iTunes U/History 106B (-only)
Spot the difference?
So in other words, I cannot find these Podcasts all in one place on the iPod - to put it another way - iTunes U in one section has Old Spice but not History, and iTunes U in another section has the History but not the Old Spice! I could go on, the History appears under some, but not all of the Music Menu subsections while the Old Spice is not on the Music Menu at all!
It's mind numbing! It's one area where Apple doesn't appear to have got it right and unfortunately, I don't think that it will ever be sorted out. Often, this issue can be as a result of how the Podcast producer tags their videos, which may explain why the problem has just started. But how anyone sorts that out is beyond me too because different models of iPod act in different ways.
So have a good look through your iPod for the missing episodes, good luck, let us know how you get on, do you find them?
Phil
P.S. On my Videos/Music Videos menu header, the iPod states "No Videos" but when I look in there, I find two videos! ??