Yeah, same problem with me. You should change your settings and disable “Rebuild sitemap if you change the content of your blog” and then rebuild the sitemap manually.
It’s a temporary fix I found for now.
Wish the plug in author would update for the latest version of wordpress…
I have the double // for child categories that I deleted and no longer use. Using ulgaming’s suggestion didn’t work. I believe those childs are in the database somewhere as I’ve tried different sitemap plugins and the same happens — so I know it probably isn’t a plugin issue. More of a database issue and not knowing how to delete them permanently…
/j
