Not sure if this is new in the beta, but I discovered that drag/dropping post meta boxes in the post edit screen empties the form input fields for the Post Format in the dropped meta box. Even when releasing on the same place. This can be associated with just radio inputs, since it happens also with custom meta boxes. Maybe it’s just a visual issue, but it can be confusing.
I dragged and dropped all the defaults (tags, categories, etc) without any loss of data. Is this happening on every single meta box? Have you tested with plugins off and the default theme to make sure it’s not something bibbedly there?