Why won't iTunes play podcasts in my Smart Playlist?

I have a Smart Playlist that selects a set of music and podcasts for me to listen to throughout the day. However, after three days of only listening to music and zero podcasts, I pared it down so there was a small, equal number of podcasts and music. After all the music played... it just stopped. Here's a screenshot showing this:

In this screenshot, I double-clicked the podcast on top and did nothing else. I expect that the two songs and 4 other podcasts would show up in the "Up Next", but only the music shows up in the "Up Next" list. This is frustrating, as it completely defeats the purpose of this Smart Playlist.

Why isn't iTunes playing my podcasts, and how do I get it to do so?

I've also found that Podcasts don't have the same options as songs for some reason:

As you see, the podcast doesn't have the same queuing options as the music.