We are using 1.6.0-rc.3 and the necessary updated plugins
We have a page with slugs and when those slugs contain a TinyMCE edit control, moving a slug causes the content in the TinyMCE edit control to no longer be displayed. Any other fields in the slug are fine.
If you save the page, all is well, the slug has repositioned and content is still there. So it is just a display issue. But it is rather disconcerting to the user updating the page.