if one uses the tinymce templates, he does a mess when update an entry:
the .meta is deleted,
the .html file is renamed: bla.html becomes bla-1.html

Debugging the code I've seen that blogEntry.getBlogCategory() returns something like:

_blogCategory= FileBackedBlogCategory (id=309)
_blogEntry= null
_blogUser= null
_category= null
_categoryURL= "http://localhost:8080/blojsom/blog/default/null"
_description= null
_logger (FileBackedBlogCategory)= Log4JLogger (id=281)
_logger (BlogCategory)= Log4JLogger (id=282)
_metadata= null
_name= null
_parentCategory= null
_subcategories= ArrayList (id=319)

probably this is the source of the problem