‘Elephant in the room’ does have a very different meaning than the phrase she used.
The elephant in the room is something obvious that everyone is ignoring.
The phrase she used (at least in the UK) would mean something unpleasant that is hidden or non-obvious. Seems that’s the US meaning as well - apart from in both countries also meaning: “I am an elderly racist”.
The non-racist alternative would be ‘fly in the ointment’.
