Hi the problem is that the documentation says that update_field() return TRUE if all ok, FALSE in case of failure.
Instead is also returning FALSE if the value is not updated (because the value you pass to the function is the same with the current DB value).
It should be CLEAR that the function return FALSE not only in case of failure.
(and I agree that the problem is also at WP level).
This because if you write a code like this:
if(!update_field(…)) handle_error(…);
you get crazy (because in some case there is no error to handle !)
