I am having the same issue. I upgraded to 2.80 and lost my catagory structure. So while I was rebuilding it worked o.k. until the first time I added a banner/image to one of the catagories. Now everytime I add or modify a catagory I get '...' added to the end of the URL and the Catagory name. If I try to fix it I get '......' and so on.

Check at http://www.klvance.org to see what I am talking about. I saw it on the site listed above as well.

Kevin aka
Boufa