I’m having the same issue in 2.1
When trying to edit a post I get a blank screen in Safari (or a Download in Firefox) after hitting save. I switched to the Google Sitemaps 3Beta and am not even able to edit posts. I get a ‘lost network connection’ when I click the edit button.
All problems go away when I dissable Google Sitemap Plugin.
I didn’t have the issue in 2.0.6.