Yeah, I have had that issue too. I have to hit reply twice. Then it looks like I posted twice, but when I refresh, it deletes the second duplicate post.
I was having issues yesterday doing a new post. It would take me to a default 'bad page' message in my browser. I finally got it to post by
making sure I had actually reselected the category
setting the second pull down to bug/task
adding a tag...
Not sure why, but then it let me post.
good luck chasing it down.
t.