Some purchased TV shows download to iPad, others do not

OK. I know how to get my purchases that are 'not on this iPad' to download - generally.

I recently purchased four television episodes - using my Macbook Pro. They downloaded fine.

Next, I went to my iPad to sync them via iTunes and a cable - didn't work. Don't remember the error.

So, i just went directly to iTunes on my iPad (3) (iOS 6.1.3) and tried to download from 'recent purchases - not on this iPad'. The four episodes show in my list. I click the little cloud. Two download and show up in Videos. Two download (progress bar, etc.), but never appear anywhere. I have free space. I re-booted my iPad.

Thoughts?

Thanks in advance.