I would imagine it's because of the downvotes cast by @drakos yesterday, bringing this post down to a low enough value that the Condensor interface running Steemit.com (and other tribes) doesn't display the content.

Not a big deal. I would imagine the posts over the next few days will be fine (unless the same thing happens again, that is).

EDIT:

Looks like it's not an issue if your main steem-interface is SteemPeak