I have 5 WP websites. Updated the first two to 3.5 and noticed that when I went in to make a post with links, I would post, then when I went back to update or make changes, it would erase the links I had and I would have to redo ALL the links on that post.
I have 2 membership websites that have many links I need to update. But with this error, I am afraid to touch it so I stopped updating and continue to use the old version.
On one site with few links (tourguidenotebook.com) I disabled all plugins and even went to 2012 theme and still had the problem.