Mike,
there are no known bugs at the moment. But I expect confusion regarding "global" key bindings, rule of thumb: more specific key bindings have HIGHER priority, than global. For example, if you assign action to, say, global => "hold 1", it will work in menu, about, book info etc, but not in book reader. Book reader has it's own actions bound to "hold 1" (scroll to the first page). If one wants "hold 1" to work in book reader, he/she has to explicitly assign actions for "book" keys.
I hope you can decrypt what I wanted to say...