Huh, that's odd. I know that'll happen if you change the title at eBay but it shouldn't happen if you're doing it through Auctiva.
One thing you might try is this: Since the recent updates here you can now change the Template Title in the "Template" section of the listing form. Be sure to check and see if it says what it's supposed to say. If not, copy your new title in that field.
Of course, that means you need to use the Create Similar feature instead of just editing existing listings.
Maybe that'll work as a temporary fix, but definitely file a support request if you haven't already.