I can't tell for sure right now as I'm reinstalling everything on my dev box but....
I think this is an issue with the different ways you can embed emotes in a message. One way is to embed with links so after you add the emote in your message it looks like [/someEmote]. The other way the emote shows up right away as a graphic.
With out having actually tried this yet I'll bet if you go into the Forums configurations and change this the problem would go away.
For the Forum team: Here I'm typing the problem word.
You'll probably see a broken link above instead of the word mentioned in the subject.