I'm bumping into odd behaviour as well..
first, If I translate a child-page , it creates a translation for both the child and it's parent page (this seems logical). If I then go back to translate a sibling (so a child of the same parent page which was just translated) , it creates a translated version for the page , but I cannot see it in the translated site-tree.
Another bug pops up when you click "show deleted pages" in a translated site-tree. It now shows the sitetree of another language.
ps(Is this the right thread to talk about the new Translatable features?) ....