I have seen a couple of bad posts over the 48 hours. I assume a fix has already gone out.
The issue appears whenever you try to edit the code AFTER you had submitted the snippet and pasted into a gray box. As long as you didn't attempt to modify with it, it was fine. It used to add the extra "</b>" tags into the HTML.
Instead of making changes directly, you had to use the HTML editor to make modifications.
Mark the best replies as answers. "Fooling computers since 1971."