I don't know if others have experienced this, but it's happened to be a couple of times previously, figured this time I'd bring it up.
Sometimes, the playlist URI link loses it's mind. The app will show the playlist and it will play normally, but the playlist gadget on the community site is fubared. See the screen shots below.
I have figured out how to "fix" (from this happening previously) it by creating a new playslist in the app, copying all the songs to it from the old playlist, deleting the playlist and renaming the new one to the old name, then editing the community posts to have the new URI link.