Moving Topics to an empty category

I have just created a new category and moved two topics to it but they did not appear there. The category was empty so I created a new topic in there. When I'd submitted that topic the other moved topics also appeared.

So it would seem moving topics to an empty category is a problem.

[EDIT]
Have just confirmed this with my Test forum. I had an empty category already created and moved an old topic to it. - Not there.
Created a new topic in the empty category and after submitting it, the moved topic also appeared.