Ci's probably lived in the states now longer than she did in the UK. Probably natural for her accent to get more Americanized, especially being around so many American broadcasters, who have their own specific tone.
Some people never lose their accent regardless of their time in exile, but English and American accents are not that far off from each other in relation to say Hungarian/Magyar vs American. Its very difficult to iron out your Hungarian accent into a perfectly sound American one due to considerable lingustic differences.