There's a long-standing bug here. Sometimes after a post is submitted, a word in it will disappear. Oddly enough, it's not always immediate. Example:

Back when I was studying for my private pilot's license, my instructor once asked me out of the blue...

When I posted it originally, a separate line at the end read simply, "Money." When I posted it, that line was there. But later after someone commented on the post, only the period remained. I edited the comment to put "Money" back in. Later the same thing happened. Most recently I edited it again so that it was a complete sentence, and not on a separate line. The first time this happened to me when I first joined this site, I assumed I had mis-typed, but as this came up again and again I realized the system was dropping words, seemingly at random (though there might be some hidden logic that's resulting in this odd behavior). This does not happen on every post, but occasionally.

The key is that it seems to happen after someone posts a comment.