Funny thing. You have either misconfigured Q2A or found a glitch. Most likely the former :)
Go to Admin > Posting and look for the Censored words text area at the bottom. You should have an s in there. I would ask you to copy that text and paste it here to check that but I'm pretty sure it will be nasty So try to look for the extra s and then remove it.
You can also remove all of the text in there and see if after that the posts are correct. That is the quick diagnose, as you can add it back later if that didn't fix it.